سید حسین رضوی

Calcification of the carotid artery wall can serve as a primary pathology that early detection can prevent adverse outcomes in patients. Therefore, in this study, the prevalence of carotid artery calcification in an Iranian population was assessed by CBCT radiography.

In this cross-sectional descriptive study, 320 CBCT images taken at a private oral and maxillofacial radiology center in Tehran City during 1395-1399 were reviewed. The patients’ age and gender were recorded, and these images were used to examine the carotid artery for calcification. Data were analyzed using SPSS17 software along with Chi-Square and t-test analyses.

Out of all radiographs, carotid artery calcification was diagnosed in 11 cases (3.4%) among patients with a mean age of 52.55±20.07 years, including 8 men and 3 women A statistically significant association was found between carotid artery calcification and both sex (P = 0.048) and age (P = 0.000) of the patients.

Based on the results of the present study, the frequency of carotid artery calcification was low in the study population. The frequency of this complication was higher in older people and men.

The hidden curriculum is the strongest way to convey the values of the medical profession. Adequate identification and attention to it can make a better and more comprehensive understanding and improvement of clinical skills training. The aim of this study was to explore the experiences of dental students using the hidden curriculum.

 In this qualitative study, the content analysis approach was used to discover the hidden aspects of students' learning from their professors. Data were collected through in-depth and semi-structured interviews with 20 postgraduate students of Shahid Sadoughi dental school in Yazd in person and by telephone. The interviews were transcribed after recording. Sentences and statements related to the purpose of the study were extracted, coded and classified from the text of the interviews. The content analysis method was utilized.

The hidden curriculum from the students' perspective was identified in four main themes: professors’ interactions, dealing with errors and problems, educational rules and regulations, and interpersonal discrimination, and twelve subthemes. These themes indicated the importance of practical training as well as the role modeling of students by their professors, especially in the clinical field.

The results of this study show the effect of the hidden curriculum in teaching and learning students, and the results of this study can be useful in improving the capabilities related to the educational role of dental professors.

Cast iron has a special place in various industries due to its low price and production ease. It seems that the use of machining chips is a suitable solution for alloying and increasing the mechanical properties of cast iron. In this research, continuous swarf resulting from IN718 machining with aligned placement in the foam was carried out. After placing the swarf, GG20 cast iron was cast by the lost foam method. After casting, the composite and simple samples were normalized at 900ºC. Microstructural studies were showed that the structure contains type A and C graphites and fine pearlites in the presence of chips. Also, the presence of swarf disturbed the solidification balance, which ultimately resulted in the presence of ferrite areas in the vicinity of the swarfs. As a result of normalization, the C graphites of the simple sample were removed entirely. Allotriomorphic ferrite was formed in the composite sample at the interface, and fine A-type graphites were distributed in fine pearlite matrix. The addition of swarf increased the hardness from 132 to 153 HB due to the creation of local saturated solid solution, compositing, and normalizing due to the mentioned microstructural changes the hardness of both samples increased to 148 and 180HB. Swarf acted as a barrier against crack growth causing the formation of soft phases and finer pearlite and graphite. The sample’s impact energy increased from 3 to 3.5J. With normalizing, the fracture energy of the simple sample increased to 4.12J while the composite sample to 6.1J.

The evaluation of radiomorphometric indices of the mandible can aid dentists not only in forensic investigations but also in diagnosing developmental abnormalities, age-related changes, and gender-specific characteristics that are crucial for treatment planning. This study aimed to evaluate radiomorphometric indices of mandibular bone on panoramic radiographs for estimating gender and approximate age.

Methods and Materials:

 In this descriptive-cross-sectional study a total 180 panoramic radiographs were retrieved from the Oral and Maxillofacial Radiology Department of Yazd Dental School. Seven different indices were measured: upper ramus breadth (URB), lower ramus breadth (LRB), Condylar ramus height (CH), Projective ramus height (PRH), Coronoid ramus height (CRH), the Gonial angle (GA) and Antegonial notch (AN). Linear and angular measurements were performed on the images. Data analysis was conducted using SPSS 17 with ANOVA, t-tests, linear regression, and logistic regression.

The panoramic radiographs were taken from 90 male and 90 female patients with a mean age 39.29 ±15.9 years. For age estimation in males, the most important indices were the AN, GA, PRH, and CRH. In females, the CRH and LRB were the most relevant indices. For gender determination, the AN, PRH, CRH, and CH indices can be used in descending order of significance. Using the prediction equation, gender determination accuracy was 77% for males, 86% for females, and 82% overall. Mean values for all parameters were higher in males than females.

Morphometric analysis of mandibular ramus indices on panoramic radiographs is a reliable method for gender determination and age estimation in the Iranian population. These findings support the use of mandibular ramus indices in forensic dentistry for population-specific applications.

Identification and completely cleaning the extra root canals are crucial for the success of endodontic treatment. Prevalence of the middle mesial canal (MMC) in mandibular molars is still a topic of debate due to the complex and diverse anatomy and morphology of these teeth. This study aimed to investigate the prevalence of MMC in mandibular molars using CBCT radiography.

In this descriptive cross-sectional study, 300 CBCT images obtained between 1995 and 2019 in a private oral and maxillofacial radiology center in Yazd, Iran, were evaluated. The first and second mandibular molars were examined for the presence of MMC based on the patients' age, gender, tooth location, and type. Data were analyzed using SPSS 17 and the Chi-square.

Out of 300 mandibular molars (122 first molars and 178 second molars), MMC was found in only 18 teeth (6%). The prevalence of MMC was significantly higher in the first molars (18 cases) than in the second molars (0 cases). Twelve MMCs were observed in females and 6 in males. 12 MMCs were located in the left side and the rest in the right side. The mean age of individuals with MMC was 37.33±15.27. There was no statistically significant association between the presence of MMC and age, gender, or tooth location (P > 0.05), but the prevalence of MMC was higher in the first molars than in the second molars (P = 0.0001).

The prevalence of MMC in mandibular first molars was low in the studied population and was not detected in mandibular second molars. Nevertheless, the possibility of MMC should be considered during the treatment of teeth.

Canalis Sinuosus (CS) is a bony canal in the upper jaw.  This canal has branches towards the anterior ridge and the teeth, which can be exposed to damage during dental procedures such as implants, resulting in paranesthesia. The purpose of this study was to determine the frequency of CS in the anterior region of the maxilla by CBCT radiography in a private radiology center in Yazd City in the last 2 years, to familiarize dentists with this anatomical variety and prevent complications.

In this cross-sectional study, 218 CBCT images were selected. Images are related to the patients in the age range of 24 to 80 years. Axial, coronal and sagittal sections are reconstructed by an oral and maxillofacial radiologist. The images reviewed by two radiologists. Then, age, sex, frequency, location of the canal ending, bilateral or unilateral, sub-branches and the location of the canal in the vertical and anteroposterior dimension were checked. The results were investigated by SPSS version 16 software with Chi squared and T-test statistical tests.

The reviewed images belonged to 112 (51.4%) women and 106 (48.6%) men. The frequency of CS was 96.3%. The most frequency was found in women in the age of 24-44 years (62.8%). The 95.4% was reported bilaterally. In the examination of the Accessory canals, they were not seen in 141 people (64.7%). The accessory canal (AC) was reported more frequent between central and lateral incisor. In this study, using the Chi-Square test, there was no statistically significant relationship between the presence of CS and age (P=0.188) and gender (P=0.162).

Due to the high frequency of CS and its branches in the anterior region of the maxilla, in order to avoid unwanted consequences during surgery, the desired area should be examined.

The third root of mandibular molar teeth is the most important normal anatomical variation in these teeth. Failure to recognize the presence of this root is one of the most common reasons for treatment failure in these teeth. Therefore, the aim of this study was to investigate the prevalence of Radix Entomolaris in the mandibular first and second molars in the population of Yazd City using CBCT imaging.

In this study, 217 CBCT images prepared in an oral and maxillofacial radiology clinic were examined. The presence of the third root in the first and second molar teeth of the mandible was investigated according to the gender of the patients and the side of the tooth placement. Data were analyzed using SPSS16 software and Chi-Square statistical test. 

The prevalence of Radix Entomolaris in the present study in first molar and second molar teeth was recorded 5.1% and 1.8%, respectively. It was reported that its bilateral prevalence was 1.4%. In unilateral cases it was observed more on the right side. The occurrence of Radix Entomolaris had no statistically significant relationship with gender (P>0.05).

The overall frequency of Radix Entomolaris in the population of Yazd City is 6.9%. Its frequency is more likely to be unilateral, mostly in the first molar and without the influence of gender.

In recent years, CBCT imaging has found many applications in dentistry due to its advantages such as 3D images, ease of imaging and the possibility of data reconstruction. The aim of this study was to evaluate the knowledge and attitude of dental residents and students of Shahid Sadoughi University of Medical Sciences towards the need to prescribe CBCT in 2022-2023.

the current study is a cross-sectional and descriptive study.146 general dentistry students and 24 dental residents participated in this study. 23 questions in the field of knowledge and attitude about the use of CBCT were used. The validity of the questionnaire was confirmed by using sources, valid scientific articles and by presenting and consulting radiology specialists. To determine the reliability, retest and Cronbach's alpha coefficient was used. Finally, the results were statistically analyzed by SPSS software version16 using chi-square, t-test and correlation tests.

The level of knowledge and attitude of general students was higher than dental residents. Moreover, there was a significant difference between the level of knowledge and attitude of students with their duration of study at the university, so the higher the academic year, the lower the knowledge and attitude.

The results of the present study showed that dental students of Shahid Sadoughi University of Medical Sciences have a relatively moderate knowledge and attitude about the use of CBCT.

Given the high prevalence of maxillary sinus lesions, the significance of their early diagnosis, and the role of radiography in the diagnosis, the purpose of this study was to assess the knowledge of senior dental students in Yazd City, Iran in 2021 regarding radiographic changes of the maxillary sinus in panoramic radiographs.

In this analytic study, 53 senior dentistry students in Yazd City in year 2021were selected in the form of a census and their knowledge were assessed using a questionnaire containing 20 knowledge questions. Data were analyzed through SPSS ver.17 software and using t-test, ANOVA, Chi-square and fisher-exact.

In this analytic study, 53 senior dentistry students with an average age of 25.6 ± 2.3 participated in this study. Their average knowledge score was 7.13 ± 2.12 out of 20. There was no significant difference in the average score of knowledge according to age, sex, type of entry and GPA of students (P<0.05).

According to this fact that senior dentistry students in Yazd City have insufficient knowledge about radiographic changes of maxillary sinus; It seems necessary to revise the educational methods according to the educational curriculum.

Reduction the error intraoral radiographic image is very important for accurate diagnosis of dental diseases and reduces the patient and clinician dose. The aim of this study was to determine the prevalence of intraoral radiographic errors made by students of Shahid Sadoughi Faculty of Dentistry in Yazd City.

In this descriptive-cross-sectional study, 1900 samples of periapical radiographs were taken using digital periapical bisect angle method and bite-wing radiographs were evaluated. Patients referred to Oral and Maxillofacial Radiology Department of Yazd Dental School in 2018-2019 were evaluated by simple sampling method. During 4 months, the researcher examined 25 radiographic images for cone cut errors, horizontal and vertical angles, and incorrect film placement. Also, if the radiography was repeated, the number and reason were also recorded. The recorded data were entered into SPSS version 16 software and the prevalence of each error was reported.

The errors in this study included incorrect film placement (32.4%), incorrect horizontal angle (28.2%), incorrect vertical angle (24.6%), cone cut (23.9%) and radiographic repetition rate (33%). In periapical radiograph, the frequency of errors was observed in maxilla (54.6%), mandible (45.4%), anterior (22.5%) and posterior (77.5%). The frequency of errors in bite-wing radiograph was estimated to be lower than periapical.

Based on the results obtained in the study population, the most common error included incorrect placement and wrong horizontal angle, which were led to the most repeated radiographs and observed mostly posterior of maxilla, which emphasizes the need for further training to correct the errors.

Most third molars eventually need to be extracted, and this tooth has the most varied and unpredictable root position of all teeth. Therefore, considering the importance of accurate diagnosis of the roots of molar teeth before surgery to reduce its surgical complications, the aim of this study was to evaluate the ability of panoramic radiography to diagnose the situation of roots of third molars. the relationship of the roots to each other and the angle of the crown to the root in panoramic and clinical radiographs, respectively, using Romexis viewer and digimizer software were investigated.

In this cross-sectional-analytical study, 104 third molars of 93 patients referred for wisdom tooth extraction were examined clinically for the number of roots, the relationship of roots to each other and the angle of the crown to the root in panoramic radiography using Romexis Viewer  software and clinically after providing photograph and measuring the angle using digimizer software.

In evaluating the roots of third molars, the accuracy of panoramic radiographic interpretation regarding the number of roots was 63.27% and in the presence or absence of root, adhesion was 55.89%. In addition, Pearson correlation analysis showed that there was a significant relationship between the reported angle in radiographic interpretation and the actual angle (r = 0.318 and P value = 0.001).

Therefore, panoramic radiography is a valuable guide for third molar surgery. It is only necessary to consider its high error rate in terms of morphological details such as the number of roots and their relationship to each other.

Early treatment of dental anomalies and oral/dental lesions can prevent maxillofacial abnormalities and other complications. Since in most cases these lesions are asymptomatic, they are often discovered randomly in different radiographic images. Therefore, the aim of this study was to investigate the incidental findings on digital panoramic radiographs of referrals to Maxillofacial Radiology Department of Yazd Dental School.

In this descriptive cross-sectional study, 1949 panoramic radiographs of patients referred to the Department of Maxillofacial Radiology of Yazd Dental School in Apr 2019_ Apr 2020 were studied. Age, gender, type of lesion / anomaly, position and jaw involved were recorded in the study information form. Data analysis was performed via SPSS16 statistical software and Chi-square test.

A total of 2915 lesions / anomalies were diagnosed. The frequency of these lesions / anomalies was higher in men (57.5%), middle-aged people (48.6%), mandible (69.3%) and left side of the jaws (76.8%). There was a statistically significant difference in the presence of lesion / anomaly in terms of age, sex, side and jaw involved (P-value = 0.0001).

Considering the frequency of random findings in panoramic radiographs, it seems that this radiography is useful for detecting many lesions and dental anomalies in the initial examination of patients. It is recommended that dentists examine the radiographs more carefully.

Patients, oral health care staff anddentists are exposed to infections and infectious microorganisms during dental imaging. The aim of this study was to evaluate the knowledge and practice of general dentists in Yazd City about infection control during the preparation of intraoral radiographs.

This analytical cross-sectional study, examined the knowledge and practice of 81 active dentists in Yazd City who were selected based on convenience sampling method through a questionnaire. To analyze the data, SPSS 16 ,and Pearson's correlation coefficient as well as One-way ANOVA were used.

The mean age of the participants was 36.45 ± 9.66 and their mean work experience was 10.03±8.28 years. The mean score of knowledge about infection control during intraoral radiographs was more than 50% and it was evaluated as moderate. There was no statistically significant difference between the mean score of dentists' knowledge in terms of gender (P=0.623), age (P=0.849), work experience (P=0.824) and the year of their graduation (P=0.860), but there was a statistically significant difference between the mean score of dentists' knowledge according to their university of study (P=0.015), so that Yazd School of Dentistry graduates had significantly less knowledge than graduates of other faculties.

Considering the importance of infection control in dental radiology and the mean score of dentists' knowledge in the present study, which was moderate, therefore, the need to improve dentists' awareness in this field is emphasized

In the present study, IN738LC superalloy ingot was re-melted and cast, then heat treated under ‎standard conditions. Microstructural studies with field emission scanning electron microscopy ‎‎(FESEM) equipped energy dispersive spectroscopy (EDS) showed that after re-melting and ‎controlled casting, the amount of porosity and size of γ' precipitates decreases. Also, with ‎applying the standard heat treatment cycle, the primary γ' precipitates less than 1µm in size and ‎cubic morphology and nano‏spherical‏ ‏secondary γ' precipitates appeared and eutectic γ-γˈ ‎regions were completely eliminated. Vickers hardness test results under a load of 10 Kg showed ‎that the lowest hardness is related to the solutionized sample due to remove the coarsened γ' ‎precipitates and the highest hardness (833 H.V.) is obtained after aging. According to the results ‎of the tensile test at ambient and 750◦C temperatures, by re-melting and applying the standard ‎heat treatment due to structural modification, strength and elongation increased at both ambient ‎temperature and 750◦C. Also, with applying the standard heat treatment, failure mechanism of ‎IN738LC superalloy was transferred from brittle trans-dendritic failure to brittle inter-dendritic ‎failure with little footprints of ductile fracture.‎

Due to preventing unnecessary exposure to x-ray, the dentists must acquire adequate information about radiography.

This descriptive cross-sectional study was conducted on general dentists working in Yazd City, selected by convenience sampling method. The data were collected using a three-part questionnaire, the first part included demographic information of the dentists (age, gender, work experience, education level), and the second part contained the effective clinical findings in radiography (patient age, sex, history, radiographic costs, patient preferences, clinical observations, type of radiographic imaging system).

120 dentists with an average age of 37.38 ± 9.88 were in this study. The greatest impact factors on decision making by dentists in prescribing radiography were: surgical treatment plan (87.5%), toothache (75%), poor oral hygiene and heavily restored dentition (73.3%) and those who afraid of X-ray exposure were the least effective factors. The top radiographic choice of most of the dentists for diagnosis of occlusal caries was periapical radiograph, with 55%, even though according to the existing researches bitewing radiography would be the effective method. The top choice for the diagnosis of interdental caries was bitewing radiography with 88.3%, which matched the existing researches.

Based on the results of this study, it can be said that the dental community has little knowledge in the field of radiography for the diagnosis of occlusal carieshowever most of the dentists were right about diagnosing interdental caries. Therefore, it is important to hold retraining courses in order to maintain and improve the level of awareness of dentists and their familiarity with the latest radiographic techniques.

Dental anxiety is one of the important reasons for avoiding dental treatment and, in the long time it can result in decrease in oral and dental health as well as decrease in quality of life of patients. Furthermore, the presence of anxiety in the patients and its repetition in the examination of patients can also affect the efficiency of dentists. The aim of this study was to investigate the effect of verbal education on the anxiety of patients with irreversible pulpitis

In this clinical trial, 96 patients with irreversible pulpitis of maxillary premolars referred to Khatam-ol-Anbia Specialty Clinic in Yazd, Iran were randomly studied into case and control groups. Before the start of the treatment, a verbal description of the therapeutic measures and type of devices was given to the case group patients for 15 minutes, but no verbal education was given to the control group. Patients completed the Standard Dental Anxiety Scale (DAS). The data were statistically analyzed using SPSS17 software and T-test and paired T-test.

Before the intervention, the anxiety score in the control group was 10.46 and in the intervention group was 11.71 (p > 0.05), and after the intervention, it was 8.65 and 8.21 respectively (p > 0.05). The rate of anxiety reduction in the intervention group was significantly more than the control group (p =0.017).

The reduction in anxiety score in the intervention group was significantly more than the control group, which was the result of intervention and it can be said that the verbal explanation was effective in reducing the anxiety of the patients.

In the present study, the service-exposed gas turbine blade was rejuvenated after 80000 hr of service. In this report, the effect of cooling on liquid nitrogen and cryogenic after two stages of solution (full and partial) was investigated. Microstructural studies by scanning electron microscopy (SEM) showed that increasing of the cooling rate in full solution resulted decrease in the size and percentage of volume fraction of γ´ precipitates after aging. whereas the cryogenic effect at full solution stage was less than the cooling rate. The effect of high cooling rate on partial solution was a decrease in γ´ precipitates volume fraction after aging compared to similar effect on full solution stage. Cryogenic treatment after partial solution increased the secondary γ´ precipitates volume fraction and size till 230 nm. High cooling rate of partial solution resulted in the maximum of hardness after aging and high cooling rate of full solution resulted in minimum of hardness after aging.

The aim pf this study was to compare the effect of the premarital preparation program based on Olson’s model and domestic premarital counseling package on couples’ problems during engagement period. This quasi-experimental study was performed using pretest, posttest and follow-up design with a control group. The statistical sample consisted of 45 couples during their engagement period in Yazd. They were selected by a purposeful sampling method and were assigned randomly into two experimental groups and one control group (15 couples each). All groups completed the Couples Pro-blems Questionnaire during the pre-test, post-test and follow-up stages. Then, the difference between groups were compared by analysis of variance with repeated mea-sures and a post hoc test. The results sho-wed that the mean score of problems during engagement time in both experim-ental groups decreased significantly in post-test and follow-up phases (p<0.0005), but there was no significant difference between the two experimental groups (p>0.05). The findings of this study confirm the effectiveness of both the prem-arital preparation program based on Olson’s Model and the domestic prem-arital package on reducing couples’ prob-lem during engagement period.

In this study, IN738LC super alloy samples were solutionized at 1210 °C for 5 hours. After solutionizing, the samples were cooled in both air and liquid nitrogen. One of the air-cooled samples after reaching the room temperature was stored in liquid nitrogen for 2 hours. To investigate the effects of high cooling rate and sub-zero operations on the microstructure and hardness, the samples were characterized by scanning electron microscopy (SEM) and hardness test. Deeper sub-zero operations reduced the size of the sediment to 117 nm. While cooling in liquid nitrogen reduced the size of the sediment to 76 nm. This suggests that the cold weather in the air has provided the opportunity for growth to precipitate. By increasing cooling rate and keep at deep zero, the hardness of the samples decreased, so that the minimum hardness was related to the sample stored in liquid nitrogen. The results of this research can be applied to new blades after casting and also under service and to help improve the heat treatment process.

In this research, after pressing in a cylindrical mold, the AA 7075 alloy swarfs were melted and cas t in a wet sand mold. After rolling and cutting, sheets with two different thicknesses of 6 and 20 mm were obtained. The sheets after homogenization were solutionized at 485°C for 30 and 90 minutes, respectively, due to differences in thickness and thermal gradients. The solutionized samples were quenched in 3 polymer solutions containing 10, 30 and 50% Poly Alekylene Glycol. The results showed that by melting, cas ting, rolling and heat treatment of AA7075 alloy swarfs similar properties to this alloy is achievable. Micros tructural s tudies by optical microscopes (OM), Field Emission Scanning Electron Microscopy (FESEM) and X-ray diffraction (XRD) showed that by increasing quenching rate after Solutionizing process, precipitation increases during aging. It can also be deduced from the tensile tes t results that increasing the quench rate and, consequently, increasing the internal energy and the driving force diffusion of alloying elements is going to increase precipitation, which leads to increasing the alloy hardness and decreasing its s train after aging. Also, microscopic images of fractography confirm this by illus trating characteris tics of the brittle failure.

The aim of this study is to investigate the effect of Premarital Prepare counseling on marital satisfaction of Couples in Engagement Period. The research was quasi-experimental using control group, pre- and post test and follow-up design. Statistical sample was 30 couples in Engagement Period were selected by purposive sampling among couples settled in Yazd (spring 1396), and were randomly assigned into two controls and experimental groups .then the experimental group participated in 7 sessions for Premarital Prepare counseling. Both groups completed marital satisfaction questionnaire (ENRICH) in pre and posttest and follow-up. At the end, the results between 2 groups were compared through mixed analysis of variance .The results showed a significant increase in the mean of marital satisfaction in posttest in the experimental group (p<0.05) .The findings of this research, confirmed the effectiveness OF Premarital Prepare counseling on marital satisfaction of Couples in Engagement Period and it could be effective for determining counseling and educational planning for such couples.

Maintaining the current share of public transportation has direct relationship with users’ satisfaction. Determining users` satisfaction depends on many factors, which usually are divided into 5 categories: safety, comfort, reliability, service characteristics, and quality of providing information for users. This article suggests. The model used the data collected by a questionnaire which has three mail sections. The first section questions about satisfaction of users and the importance of each of these attributes have been asked, the second part is about the trip characteristics and the third part collected passengers’ socioeconomic characteristics. The proposed model studies Satisfaction Index with using the mean and variance, and simultaneous effect of satisfaction and importance of attributes. Analyzing of this model shows that those attributes which have the most impact on the users` satisfaction of system are Travel Safety, reaching the destination on expected time, and apt air conditioning of bus. While in developed countries reliability of service has the most important role in users` satisfaction. The proposed methodologies show some advantages compared to the others adopted for measuring service quality, because it can be easily applied by the transit agencies

In this paper, effect of solution heat treatment media of IN738LC superalloy on the microstructure and hardness was investigated. Two solution heat treatment medias were selected, solubilizing in the normal or conventional furnace, and solubilizing in the salt base. For this purpose, the samples were solubilized in a temperature range of 1090-1200°C for 20-30 minutes in normal condition and 10-12 minutes in the salt bath, and then aged at 248°C in 850°C. The results of the scanning electron microscope (SEM) and field emission scanning electron microscope (FESEM) showed that increasing the heating rate improves the solution process, and with increasing the temperature and time, the volume fraction of 'γ precipitates decreased by 26% in normal condition and 29% in salt bath. The size of the residual 'γ precipitates after solution in the salt bath is smaller than normal state, and at high temperatures, due to the activation of the aggregation mechanisms, the size and volume fraction of residual precipitates in the salt bath increased compared to the normal condition. Solution in the salt bath reduced the size of the primary'γ compared to the normal condition and increased the volume fraction of the secondary 'γ after the aging. After aging, the total volume fraction of precipitates increased by about 30% and 40%, respectively, in the normal condition and in salt bath. The results showed that the secondary 'γ precipitates are about 16nm smaller than usual and the hardness of the alloy is strongly influenced by the characteristics of 'γ precipitates and the variables of the solution treatment. Increasing the heating rate at the solution resulted in a further increase in hardness after aging and a further reduction in hardness after solution, and in both conditions increasing temperature and time of solution reduced the hardness of the samples after solution and increased after aging.

In this research the effect of heat treatment offer welding (PWHT) in 650,750 and 8500C for two hours on Sulfide stress corrosion cracking resistance (SSC), welding metal Inconel 625 to low alloy steel 4130 was analyzed that was welded using Automatic TIG welding process then the mechanical properties of the joint was observed using micro hardness measure experiment (weld metal, base metal and the welding heat-affected zone) and welding metal structure using light microscopy, electron SEM(EDX), also XRD. The comparison of the microstructure in different temperatures show the least effect on microstructure in 6500C. In micro hardness measure test after post-weld heat treatment (PWHT) with increasing temperature we observed decreasing hardness of base metal and heat-effected zon and alsoincreasing weld metal micro hardness. when the temperature of post-weld heat treatment reached to 8500C phase γ" changed quickly to delta phase δ.when temperature reached to 8500C secondary phases changed to needle form. After stress testing in Sulfide environment magnetic particles (MT) was done on the samples and results showed that in the post-weld heat treatment sample 8500C tension crack is made. Pictures of stress testing(SSC) SEM sample shows that tension cracks mode is base metal cracks along the grain boundaries and it also extends the base metal to weld metal.