Microstructural evolution and mechanical properties of aging high nitrogen austenitic stainless steels

2010 ◽  
Vol 17 (6) ◽  
pp. 729-736 ◽  
Author(s):  
Zhou-hua Jiang ◽  
Zu-rui Zhang ◽  
Hua-bing Li ◽  
Zhen Li ◽  
Ma Qi-feng
2010 ◽  
Vol 129-131 ◽  
pp. 886-890
Author(s):  
Da Wei Cui

The influence of solution annealing on the microstructure and mechanical properties of high nitrogen Fe-Cr-Mn-Mo-N austenitic stainless steels prepared by MIM was investigated. The results show that the solution treatment can improve the microstructure and properties of the stainless steels significantly. The sintered specimens before solution annealing consist of γ-austenite and embrittling intergranular Cr2N precipitates, showing a low mechanical property. After solid solution annealing, the specimens reveal a fully austenitic structure without any intergranular nitrides, whose tensile properties are much higher than those without solution annealing, which is attributed to the elimination of the nitride precipitation along the grain boundaries and the greater amount of nitrogen retained in solid solution. A mixed mode of intergranular and dimple fracture happen to the specimens before solid solution treatment, while a completely tough fracture of dimple happen to those after solid solution treatment.


2011 ◽  
Vol 52-54 ◽  
pp. 1687-1691 ◽  
Author(s):  
Hua Bing Li ◽  
Zhou Hua Jiang ◽  
Qi Feng Ma ◽  
Wan Ming Li

A 25kg pressurized induction furnace with maximum nitrogen pressure 6MPa was invented to manufacture high nitrogen stainless steels. The suitable process was explored, and the analysis of radiography and macrosegregation of nitrogen of high nitrogen steel ingot was performed. The mechanical properties and inclusions of the forging ingot were also investigated. The suitable solidification nitrogen pressure can effectively prevent the formation of nitrogen porosity and macrosegregation of nitrogen. It is very important to control the purity of the nitrogen gas to a higher level for avoiding the manganese loss and decreasing oxygen content in the steel during the nitrogen gas pressurized melting process. The sound and compact macrostructure high nitrogen austenitic stainless steel with nitrogen content above 1.0 wt % has been manufactured by the pressurized induction melting method. There are mainly nonmetallic inclusions with the size less than 5μm in the HNS-A ingot. The HNS-A exhibits excellent mechanical properties.


2007 ◽  
Vol 14 (5) ◽  
pp. 330-334 ◽  
Author(s):  
Hua-bing LI ◽  
Zhou-hua JIANG ◽  
Zu-rui ZHANG ◽  
Bao-yu XU ◽  
Fu-bin LIU

Alloy Digest ◽  
1999 ◽  
Vol 48 (8) ◽  

Abstract ALZ 316 is an austenitic stainless steel with good formability, corrosion resistance, toughness, and mechanical properties. It is the basic grade of the stainless steels, containing 2 to 3% molybdenum. After the 304 series, the molybdenum-containing stainless steels are the most widely used austenitic stainless steels. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-756. Producer or source: ALZ nv.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2622
Author(s):  
Malcolm Griffiths

Austenitic stainless steels are used for core internal structures in sodium-cooled fast reactors (SFRs) and light-water reactors (LWRs) because of their high strength and retained toughness after irradiation (up to 80 dpa in LWRs), unlike ferritic steels that are embrittled at low doses (<1 dpa). For fast reactors, operating temperatures vary from 400 to 550 °C for the internal structures and up to 650 °C for the fuel cladding. The internal structures of the LWRs operate at temperatures between approximately 270 and 320 °C although some parts can be hotter (more than 400 °C) because of localised nuclear heating. The ongoing operability relies on being able to understand and predict how the mechanical properties and dimensional stability change over extended periods of operation. Test reactor irradiations and power reactor operating experience over more than 50 years has resulted in the accumulation of a large amount of data from which one can assess the effects of irradiation on the properties of austenitic stainless steels. The effect of irradiation on the intrinsic mechanical properties (strength, ductility, toughness, etc.) and dimensional stability derived from in- and out-reactor (post-irradiation) measurements and tests will be described and discussed. The main observations will be assessed using radiation damage and gas production models. Rate theory models will be used to show how the microstructural changes during irradiation affect mechanical properties and dimensional stability.


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