奥氏体不锈钢焊接接头在含硫介质中的腐蚀性

利用恒电位极化曲线法及金相显微分析方法,研究了奥氏体不锈钢手弧焊焊接接头在含Na2S溶液中的腐蚀行为.结果表明,采用A102焊条的焊缝,其耐蚀性优于A307焊条焊缝;20℃条件下,Na2S质量分数的增加加速腐蚀反应的阴、阳极过程;在Na2S质量分数一定的条件下,温度升高到80℃时,在阳极极化区有钝化现象.     

Impact toughness of tungsten films deposited on martensite stainless steel

Tungsten films were deposited on stainless steel Charpy specimens by magnetron sputtering followed by electron beam heat treatment. Charpy impact tests and scanning electron microscopy were used to investigate the ductile-brittle transition behavior of the specimens. With decreasing test temperature the fracture mode was transformed from ductile to brittle for both kinds of specimens with and without W films. The data of the crack initiation energy, crack propagation energy, impact absorbing energy, fracture time and deflection as well as the fracture morphologies at test temperature of-70 ℃ show that W films can improve the impact toughness of stainless steel.     

2205双相不锈钢模拟焊接HAZ组织与性能

采用热模拟法研究了2205DSS焊接HAZ的组织与性能，探讨了冷却时间对模拟HAZ冲击韧性的影响规律。结果表明：冷却时间对组织及性能有很大的影响，随冷却时间的延长，铁素体含量减少，奥氏体含量增加，冲击韧性增大：随冷却时间延长，模拟组织显微硬度降低，而且模拟组织中铁素体的硬度低于奥氏体的硬度：固定冷却时间t8／5时，随冷却时间t12／8的增加，冲击韧性提高：固定冷却时间t12／8时，随冷却时间t8／5的增加，冲击韧性降低。     

预冷轧对1Cr18Ni9Ti奥氏体不锈钢力学性能的影响

研究了1Cr18Ni9Ti奥氏体不锈钢经不同变形量预冷轧后的各种力学性能。结果表明:该钢具有很强的加工硬化能力,冷变形使钢的各种强度性能、弹性变形能力和疲劳性能大大提高。当冷变形量达60%后,弹性极限及最大弹性应变分别是未变形时的4.6和4倍,弹性变形能力增加了17倍;屈服强度和抗拉强度分别是未变形时的4.5和2倍;而疲劳断裂应力则分别由1×104次循环的560/56MPa提高到960/96MPa(提高1.7倍)和由1×105次循环的530/53MPa提高到860/86MPa(提高1.5倍)。60%冷轧制后伸长率为5.05%,仍保持一定的塑性。     

The internal-nitriding behavior of 310 stainless steel with and without Al and Ti additions

The internal-nitriding behavior in ammonia-hydrogen atmospheres of type-310 stainless steel and 310 to which either 2 wt.% Ti or 3 wt.% Al were added was studied over the range of 550–950°C. An Fe-24Cr binary alloy was included to assess the role of a BCC crystal structure vs the FCC crystal structure of 310 stainless steel. The BCC alloy exhibited the most rapid kinetics as expected. X-ray diffraction showed only the presence of CrN in all the alloys up to 735°C. At 850°C and above, both CrN and Cr₂N were detected. The nonformation of TiN and AlN at lower temperatures is attributed to nucleation problems. Precipitates were extremely fine (unresolvable even at 20,000×) at 563°C and became much coarser with increasing temperature. The precipitate density, size, and shape varied across the internal-nitriding zone at the higher temperatures. External scaling was noted at 850°C and above, however, it was not a continuous film. The activation energy of internal nitriding from 563–735°C ranged from 3.8 kcal/mol for 310+2Ti to 18.2 kcal/mol for 310+3Al; from 850–950°C, the activation energy ranged from 44 (310+2Ti) to 56.6 kcal/mol (310+3Al). Microhardness profiles show that an intermediate zone exists between the nitride case and the base metal. The origin of this zone is discussed.     

冲击式水轮机转轮裂纹焊接修复

介绍了采用低匹配的奥氏体不锈钢焊条，在能整体不预热和焊后热处理条件下，现场手工电弧焊进行马氏体不锈钢转轮的裂纹焊补修复，修复质量经渗透探伤检验达到了要求。     

Interfacial structure and joint strengthening in arc brazed galvanized steels with copper based filler

1 Introduction Arc brazing is a brazing method that the specimens are heated by arc[1]. It is the generic terms of GMA brazing and GTA brazing[2], and has both the characteristics of brazing and welding. Compared with traditional arc fusion welding, the s…     

Environmental effects on the stress corrosion cracking susceptibility of 3.5NiCrMoV steels in high temperature water

Constant elongation rate tests (CERTs) were carried out to investigate the effects of environmental factors of dissolved oxygen and temperature on the stress corrosion cracking (SCC) susceptibility of 3.5NiCrMoV turbine steels. Tests were conducted in pure water of various dissolved oxygen concentrations at temperatures of 50 °C-200 °C in the range of strain rates from 5 × 10⁻⁸/s to 1 ×  10⁻⁶/s. Dissolved oxygen significantly affected the SCC susceptibility of turbine steels in water. The SCC susceptibility of the turbine steels increases as the dissolved oxygen concentration in water increases. The elongation of the turbine steels tested in aerated water at 150 °C at a strain rate of 1 × 10⁻⁷/s decreased to half of that of the steels tested in deaerated water in the same test condition. And the SCC susceptibility of the steels increased with decreasing strain rate, and with increasing temperature. The increase of the SCC susceptibility of the turbine steels in the higher dissolved oxygen environment is considered to be due to the higher content of dissolved oxygen enhancing the reduction reactions of oxygen on the metal surfaces (cathode) and accelerating the dissolution rate at the crack tips (anode) by galvanic attack of an aeration cell.     

Advances in the research of nitrogen containing stainless steels

The current status of nitrogen containing stainless steels at home and aboard has been introduced. The function and existing forms of nitrogen in the stainless steels, influence of nitrogen on mechanical properties and anti-corrosion properties as well as the application of nitrogen containing cast stainless steels were discussed in this paper. It is clear that nitrogen will be a potential and important alloying element in stainless steels. And Argon Oxygen Decarbonization (AOD) refining can provide an advanced manufacture process for nitrogen containing stainless steels with ultra-low- carbon and high cleanliness.