The aim of the study was to determine the effect of proton irradiation at room temperature on ferritic/martensitic P91 and P92 steels, in particular on their hardness. In addition, SRIM programme was used to identify the proton penetration depth. The study has found that the hardness of the unirradiated P92 steel is higher than that of unirradiated P91 steel, since P92 steel contains tungsten, which produces higher level of solid solution hardening. P91 and P92 steel samples were irradiated using 1.9-MeV protons to the fluence of 1.3510 17 ion/cm 2 . It was found that Vickers hardness test values increased for both P91 and P92 steels at 0.2 kg loads. For high proton irradiation (long irradiation period) the fluence was 1.10110 18 ion/cm 2 (about ten times higher than at the low proton irradiation). With growth of irradiation fluence, the number of displacements per atom (dpa) went up from 0.043 dpa (for low irradiation) to 0.18 dpa (for high irradiation) and the hardness of steels that were under investigation increased. P91 and P92 steel samples after long irradiation were heat treated for one hour at 700 o C in a vacuum furnace. The study identified that while the chemical composition of P91 and P92 steel were almost identical, irradiated P92 steel requires twice the heat treatment to reduce its hardness to a basic value, as compared with P91 steel samples.Целью данного исследования было определение влияния облучения протонами при комнатной температуре на ферритномартенситные стали Р91 и Р92, в частности, на их твёрдость. Кроме того, для изучения глубины внедрения протонов в стали была использована вычислительная программа SRIM. Обнаружено, что необлучённая сталь Р92 твёрже, чем необлучённая сталь Р91. Сталь Р92 содержит вольфрам, который способствует упрочнению твёрдых растворов. Образцы сталей Р91 и Р92 были кратковременно облучены протонами энергией 1,9 МэВ до флюенса 1,35·10 17 ион/см 2 . Под нагрузкой 200 г их твёрдость по Виккерсу увеличилась. Затем аналогичные образцы были подвергнуты приблизительно в 10 раз более длительному облучению до флюенса 1,101·10 18 ион/см 2 . С увеличением продолжительности облучения увеличилось число смещений на атом с 0,043 до 0,18 млн -1 и увеличилась твёрдость образцов. После более длительного облучения образцы исследуемых сталей были подвергнуты термообработке -помещены на один час в вакуумную печь при температуре 700 ºС. Исследование показало, что, хотя химический состав исследованных сталей почти идентичен, термообработка облучённой стали Р92 для снижения её твёрдости до исходного уровня требует вдвое большего времени, чем термообработка образцов стали Р91.Ключевые слова: программа SRIM, сканирующий электронный микроскоп, смещение на атом, сталь Р91, сталь Р92.
Intergranular corrosion is a problem that often occurs in welding stainless steel materials. Intergranular corrosion is caused by carbide precipitation which occurs at a temperature of 850 o C, causing a reduction in chromium content in the Heat Affected Zone (HAZ). The intergranular corrosion process can be controlled by the heat treatment method after the welding process. This study aims to study the effect of heat treatment on mechanical properties and intergranular corrosion resistance of SA240 TP316L material. The variation of heat treatment were divided into three solution treatment (ST), quenching treatment (QC), and non-treatment (NT). Mechanical properties testing using tensile test while corrosion resistance testing using linear polarization using H 2 SO 4 0.1 M solution. Morphology and metal composition in the HAZ area were analyzed using SEM-EDX. Tensile test results showed that welding with ST had the lowest yield strength, ultimate strength, and elongation values compared to specimens of 407.55 MPa, 599.33 MPa, and 44.53%. Corrosion test results found that welding with solution treatment has the lowest corrosion rate compared to specimens with quenching treatment (QC) and non treatment (NT). Corrosion rate in each ST, QC, and NT specimens was 0.90; 1.03; and 2.35 mmpy. The results showed that the solution treatment process can improve intergranular corrosion resistance.
AbstrakMaterial SA 387 Grade 11 Class 1 tergolong material 1.25Cr-0,5Mo sangat sensitif terhadap hydrogen cracking serta nilai kekerasan yang tinggi setelah dilakukan proses pengelasan. Untuk meminimalkan kemungkinan terjadinya hydrogen cracking pada Heat Affected Zone (HAZ) dan nilai kekerasan yang tinggi maka direkomendasikan untuk dilakukan preheat dan post weld heat treatment (PWHT). Pada penelitian ini PWHT dilakukan dengan variabel temperatur dan holding time pada masing-masing spesimen, yaitu 590°C, 620°C, dan 650°C dengan holding time 30 dan 60 menit. Pemanasan dan pendinginan dilakukan di dalam automatic muffle furnace. Hasil pengujian struktur mikro menunjukkan bahwa perbedaan temperatur dan holding time dapat mempengaruhi struktur mikro. Pada uji struktur mikro diketahui bahwa semakin tinggi temperatur dan semakin lama holding time mengakibatkan dominasi fasa bainit semakin berkurang. Hasil uji kekerasan tertinggi terletak pada temperatur dan holding time terendah, yaitu 590ºC dan holding time 30 menit dengan nilai kekerasan 153,08 HVN pada base metal, 215,23 HVN pada HAZ, serta 239,28 HVN pada weld metal. Nilai kekerasan terendah didapatkan pada temperatur dan holding time tertinggi, yaitu 650ºC dan holding time 60 menit dengan nilai kekerasan 138,71HVN pada base metal, 173,65 HVN pada HAZ, serta 215,52 HVN pada weld metal. AbstractMaterial SA 387 Grade 11 Class 1 classified as 1.25Cr-0.5Mo material is very sensitive to hydrogen cracking and high hardness due to welding process. To minimize the possibility of hydrogen cracking in the Heat Affected Zone (HAZ) and high hardness, it is recommended to do preheat and post weld heat treatment (PWHT). In this study, PWHT was conducted with temperature and holding time variables in each specimen, namely 590 ° C, 620 ° C, and 650 ° C with holding time of 30 and 60 minutes. Heating and cooling are carried out in an automatic muffle furnace. The results of microstructure testing show that temperature and holding time has affect to microstructure. Microstructure test result says that the higher temperature and longer holding time resulting in the dominance of the bainite phase decreases. The highest hardness test result is obtained at temperature 590ºC and holding time 30 minutes with a hardness value of base metal, HAZ and weld metal respectively are 153.08, 215.23 and 239.28 HVN. The lowest hardness value is obtained at temperature 650ºC and holding time 60 minutes with a hardness value of base metal, HAZ and weld metal respectively are 138.71, 173.65 and 215.52 HVN.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.