不锈钢材料在酸溶液中耐蚀性的研究

研究了不锈钢AISI304和1Cr18Ni9Ti在几种酸溶液中的腐蚀特征。这两种不锈钢在HNO3，H2SO4，H3PO4溶液中腐蚀轻微，主要是晶间腐蚀；而在HCl溶液中腐蚀严重。以点蚀为主。不锈钢AISI304的耐蚀性优于1Cr18Ni9Ti，不锈钢中碳的质量分数越低。其耐蚀性能越好。     

00Cr20Ni20Si6高硅不锈钢无缝管的研制

通过对合金元素在不锈钢中的作用的分析,设计了1种低成本的综合性能优良的新型高硅不锈钢材料(00Cr20Ni20Si6)。采取高效、短流程的无缝管生产工艺,成功制备出成材率90%以上的00Cr20Ni20Si6无缝管材。与传统高硅不锈钢相比,新钢种的使用范围更为广泛。该无缝管材不仅室温强度高出传统高硅不锈钢100MPa左右,而且耐腐蚀性能优异;在120℃、质量浓度为98%的硫酸条件下,合金的均匀腐蚀速率为0.024mm/a;而在90℃、质量浓度为98%的硝酸环境中,合金的均匀腐蚀速率为0.53mm/a。     

氮对00Cr18Ni5Mo3Si2双相不锈钢耐局部腐蚀性能影响的研究

本文主要研究了在氯化物介质中氮对00Cr18Ni5Mo3Si2(18-5)双相不锈钢耐孔蚀和耐应力腐蚀性能的影响。结果表明,双相不锈钢中奥氏体相的耐孔蚀性较铁素体相差,故优先受到腐蚀,氮使钢的耐孔蚀性提高,实际上是增加了奥氏体相的耐孔蚀性。研究还表明,氮增加18-5钢在40％CaCl_2溶液中的应力腐蚀敏感性,是由于位错的共平面性滑移引起钝化膜的局部破裂。在中性的25％NaCl+1％K_2Cr_2O_7溶液中,应力腐蚀裂纹始于孔蚀坑,含氮的18-5钢耐孔蚀性提高,从而导致钢的耐应力腐蚀性能的增加。利用俄歇电子谱分析了钝化后钢的表面膜成分,结果表明氮在膜中靠基体侧富集,从而改善了表面膜的性能,这可能是氮提高18-5双相不锈钢耐孔蚀性能的主要原因,     

固溶温度对00Cr13Ni7Co5Mo4W马氏体时效不锈钢组织和耐点腐蚀的影响

通过显微组织分析、动电位极化曲线和均匀腐蚀全浸试验研究了00Cr13Ni7Co5Mo4W马氏体时效不锈钢固溶温度1050~1150℃对该钢组织和人工海水中的耐蚀性的影响。结果表明,固溶温度影响马氏体时效不锈钢的组织均匀性和晶粒尺寸,进而影响该钢的抗点腐蚀能力;00Cr13Ni7Co5Mo4W马氏体时效不锈钢适宜的固溶温度为1100℃,经1100℃ 1 h固溶处理后,其年腐蚀速率仅为1.09μm/a,击穿电位为300 mV。     

铌对00Cr25Ni20Nb奥氏体不锈钢焊缝凝固裂纹敏感性的影响

摘自冶金部钢铁研究总院研究生孙政的硕士学位论文,导师:陈良材、韩怀月 00Cr25Ni20Nb不锈钢是为原子能后处理工程研制的钢种。这种钢在以硝酸为主的混酸介质中具有优良的耐蚀性,但此钢的焊缝热裂纹倾向较大,其中铌起了主要作用。 本文用凝固循环热拉伸试验和横向可调拘束试验两种方法研究了00Cr25Ni20Nb钢焊缝中铌对凝固裂纹的影响规律。焊缝包括纯奥氏体和含有5%铁素体相两种。结果表明,随Nb含量增加,焊缝凝固裂纹倾向增大,当Nb含量超过1.1%时,裂纹倾向开始减少。通过多种检测手段的综合测定表明,Nb对凝固     

氮对冷变形亚稳奥氏体不锈钢1~2Cr13Mn9Ni4组织和性能的影响

在25 kg真空感应炉充氩气或大气下加氮化铬铁熔炼成不同氮含量的试验用1~2Cr13Mn9Ni4钢(/%:0.08~0.18C,0.17~0.34Si,8.11~9.27Mn,0.008~0.028P,0.007~0.032S,12.57~13.34Cr,4.05~4.65Ni,0~0.34N)。该钢经锻造、热轧成0.8 mm钢带,再进行0~45%的冷轧变形。试验研究了冷轧变形量和氮含量对该钢组织,力学性能和耐蚀性的影响。结果表明,通过降碳和加适量氮可改善Cr13Mn9Ni4钢的强度和塑性;冷变形钢在敏化状态下均有不同程度的晶间腐蚀倾向;氮有利于提高亚稳奥氏体不锈钢相组成的稳定性;氮使不含稳定化元素的亚稳奥氏体不锈钢在SO_4~(2-)介质中易于钝化,提高了在非敏化状态下的耐腐蚀性,同时明显提高了在Cl-介质中耐点蚀性能。     

沸腾稀硝酸中Cr6+对高纯不锈钢耐蚀性的影响

 研究了在稀硝酸中添加不同含量的Cr6+对高纯奥氏体不锈钢耐蚀性的影响。结果表明,Cr6+在沸腾硝酸中对不锈钢有明显的加速腐蚀作用,当Cr6+超过一定含量时,还伴随着晶间腐蚀。Cr6+浓度与腐蚀速率近似呈线性关系。     

新型高硅不锈钢的发展

国内很久以前就开发了高硅奥氏体不锈钢（Si≥4％），如00Crl4Nil4Si4、00Crl7Nil5Si4Nb、00Cr20Ni24Si4Ti等及高硅双相（Y ｜ α ）小锈钢，如1Crl8Nf11Si4A1Ti等钢号。但这些钢号均属于高硅奥氏体不锈耐酸钢或高硅双相抗高温氧化、抗硫化不锈钢。本文简要介绍国外高硅结构用钢、耐蚀用钢、耐磨用钢、耐热用钢^[1-5]的开发应用，希望能为我国高硅不锈钢的发展提供帮助。     

晶粒尺寸对Cr-Ni奥氏体不锈钢在硝酸中晶间腐蚀敏感性的影响

通过在含400 mg/L Cr6++40%硝酸溶液中浸没试验和电化学试验,发现随晶粒尺寸的减小,Cr-Ni奥氏体不锈钢晶间腐蚀敏感性随之增加,但当晶粒尺寸小于临界晶粒尺寸时,晶间腐蚀敏感性开始降低。过钝化电位数值与晶粒尺寸无直接关系,与材料本身特性有关,极化后的表面腐蚀形貌与浸没试验结果相一致。     

00Cr18Mo2铁素体不锈钢的耐腐蚀性能研究

00Cr18Mo2铁素体不锈钢具有良好的综合性能,本文就其耐蚀性能进行了研究。研究结果表明,00Crl8Mo2钢在弱蚀性介质中一般耐蚀性良好,抗局部腐蚀特别是抗氯化物应力腐蚀性能优异是此钢最突出的特点。00Crl8Mo2钢在抗点蚀性能方面优于304L而与316L不锈钢相当,退火态00Crl8Mo2钢在含氯化物沸腾溶液中经1000多小时试验而不产生应力腐蚀破裂。     

Sensitization Behaviour of Manganese‐Alloyed Austenitic Stainless Steels

Manganese is an essential alloying element in advanced austenitic stainless steels with specific properties such as high resistance to harsh corrosive environments, high strength or low material costs. These materials are often used for welded constructions which have to be highly corrosion resistant. Hence it has to be ensured that the heat input during welding does not initiate the precipitation of chromium carbide resulting in a susceptibility to intergranular corrosion. This leads to the question whether the sensitization behaviour of manganese‐alloyed austenitic stainless steels is comparable to that of the well‐known conventional chromium nickel austenites. In the present work the effect of heat‐input on the susceptibility of the CrNi‐steel 1.4301 and the CrNiMn‐steel 1.4376 to intergranular corrosion (IGC) was considered. Investigations were carried out by corrosion testing in the so‐called Strauss‐Test to elucidate the effect of the annealing temperatures on the microstructure. Furthermore, the influence of heat treatment on the mechanical properties was evaluated by tensile testing. As a result, it could be demonstrated that manganese‐alloyed austenitic stainless steels like grade 1.4376 exhibit a sensitization behaviour very similar to the conventional austenitic steel grades. The same kinds of tests on intergranular corrosion resistance can be applied for both types of materials.     

Cr-Mn-N奥氏体不锈钢的晶间腐蚀性能研究

晶间腐蚀性能是钻铤结构件用奥氏体无磁不锈钢的重要性能之一.采用不锈钢10％草酸浸蚀试验方法、不锈钢65％硝酸腐蚀试验方法以及不锈钢硫酸-硫酸铜试验方法对三种不同成分的Cr - Mn -N奥氏体不锈钢做了晶间腐蚀试验.试验结果表明,A钢种在不同的腐蚀条件下均具有良好的耐晶间腐蚀性能,该材料按0.03％C、18.96％ Cr、0.57％N的化学成分设计可以达到优良的耐晶间腐蚀性能.     

超级高氮奥氏体不锈钢的耐腐蚀性能及氮的影响

用电化学测试、化学浸泡等方法研究了超级奥氏体不锈钢00Cr24Ni22Mo7Mn3CuN(654SMO)的耐点腐蚀和耐缝隙腐蚀的性能。通过改变氮含量,研究了氮对奥氏体不锈钢的耐点腐蚀和耐缝隙腐蚀性能的影响,结果表明,氮和适量的铬、钼结合,能显提高奥氏体不锈钢的耐点腐蚀和缝隙腐蚀的能力,并且随着氮含量的增国,砥体不锈钢的耐点腐蚀和耐缝隙腐蚀的能力也增强,对比实验表明,超级奥氏体不锈钢在耐点腐蚀,缝隙腐蚀等局部腐蚀性能方面可以和镍基合金C－276媲美,甚至优于镍基合金。     

抗晶间腐蚀奥氏体不锈钢的晶界工程

Sensitization by chromium depletion due to chromium carbide precipitation at grain boundaries in austenitic stainless steels can not be prevented perfectly only by previous conventional techniques, such as reduction of carbon content, stabilization-treatment, local solution-heat-treatment, etc. Recent studies on grain boundary structure have revealed that the sensitization depends strongly on grain boundary character and atomic structure, and that low energy grain boundaries such a~ coincidence-site-lattice (CSL) boundaries have strong resistance to intergranular corrosion. The concept of grain boundary design and control has been developed as grain boundary engineering (GBE). GBEed materials are characterized by high frequencies of CSL boundaries which are resistant to intergranular deterioration of materials, such as intergranular corrosion. A thermomechanical treatment was tried to improve the resistance to the sensitization by GBE. A type 304 austenitic stainless steel was cold-rolled and solution-heat-treated, and then sensitization-heat-treated. The grain boundary character distribution was examined by orientation imaging microscopy (OIM). The intergranular corrosion resistance was evaluated by electrochemical potentiokinetic reactivation (EPR) and ferric sulfate-sulfuric acid tests. The sensitivity to intergranular corrosion was reduced by the thermomechanical treatment and indicated a minimum at a small roll-reduction The frequency of CSL boundaries indicated a maximum at the small reduction. The ferric sulfate-sulfuric acid test showed much smaller corrosion rate in the thermomechanical-treated specimen than in the base material. A high density of annealing twins were observed in the thermomechanical-treated specimen. The results suggdst that the therrmomechanical treatment can introduce low energy segments in the grain boundary network by annealing twins and can arrest the percolation of intergranular corrosion from the surface. The effects of carbon content and other minor elements on optimization in grain boundary character distribution (GBCD) and thermomechanical parameters were also examined during GBE.     

304与301B奥氏体不锈钢在线固溶热处理工艺研究

通过双道次热压缩和热轧试验研究了在线固溶热处理工艺对304和301B奥氏体不锈钢组织和性能的影响,提高终了压缩温度、冷却速度,降低卷取温度,可以改善奥氏体不锈钢微观组织,减少碳化物析出,提高抗晶间腐蚀能力和力学性能.将该工艺应用于工业生产的304奥氏体不锈钢热轧卷板,测试结果表明304各项性能得到改善,冷轧前退火工序可被在线固溶取代.     

稀土元素在铁素体不锈钢中的作用和应用前景

铁素体不锈钢(11%～30%Cr)的抗点蚀、抗应力腐蚀和抗高温氧化性能均优于奥氏体不锈钢。但普通铁素体不锈钢晶间腐蚀敏感性较高,塑性和韧性较低,焊接裂纹倾向较大。经分析得出,铁素体不锈钢加稀土元素可改善钢的凝固组织,影响碳、氮化物析出形态,细化晶粒,改变钢中硫化物形态和夹杂物成分,从而改善钢的横向韧性、焊接性能和疲劳性能。因此,稀土元素在铁素体不锈钢中的应用研究工作有广阔的前景。     

Inhibition of Intergranular Corrosion in Austenitic Stainless Steels Through Critical Near-Surface Plastic Deformation and Aging

Metallurgical and Materials Transactions A - Inhibition of high intergranular corrosion susceptibility (HIGCS) in austenitic stainless steels can be achieved by healing Cr-depleted zones through...     

Comparative Evaluation of Low Nickel and Nickel Free Lean Duplex Stainless Steels with 316L in a Variety of Corrosive Media

For many applications duplex stainless steels with their superior strength coupled with lower raw material cost have emerged as an attractive alternative to austenitic stainless steels. With emphasis on conservation of scarce resources like nickel and molybdenum there is continuing endeavour to develop essentially molybdenum free lean duplex stainless steels with low nickel content such as 2304 (23Cr–4Ni), 2202 (22Cr–2Ni), 2101 (21Cr–1.5Ni). This paper compares the corrosion behaviour of a low nickel duplex (21Cr–1.5Ni) and a nickel free duplex (21Cr–1.5Cu) with 316L stainless steel in several corrosive media. All the three alloys exhibit similar excellent corrosion resistance under boiling conditions in less aggressive organic acids such as 20 % acetic acid, 25 % lactic acid, 25 % citric acid. However, in stronger organic acids such as 5 % formic acid, 5 % oxalic acid, and mixture of formic and acetic acid, the duplex grades exhibit superior corrosion resistance. This edge over 316L continues on addition of chloride ions in these acids. In boiling 50 % nitric acid solution, the corrosion resistance of these nickel free and low nickel duplex is slightly better than 316L grade. Since 304L grade is generally used in nitric acid plants, tests were also conducted on 304L and these duplex grades were found to be more resistant. Similarly in 50 % phosphoric acid also, the duplex grades exhibit superior corrosion resistance compared to 316L grade. Alloying with nickel and molybdenum is known to give rise to significant improvement in corrosion resistance in this acid. However, even in the absence of these elements, the beneficial effect of higher chromium content is evident. Of all the inorganic acids, sulfuric acid is used in largest volume in the industries. Boiling tests in dilute 1 and 5 % H₂SO₄ indicate that nickel free copper bearing duplex is more resistant than low nickel duplex grade and vastly superior to 316L Thus nickel-free and low-nickel duplex stainless steels offer a very attractive combination of high corrosion resistance coupled with cost effectiveness in a wide variety of corrosive media.