共查询到19条相似文献,搜索用时 140 毫秒
1.
为探讨超高强度不锈钢的应力腐蚀开裂行为,采用Cr-Co-Ni-Mo系超高强度不锈钢为研究对象,利用OM、XRD、TEM等测试手段,结合腐蚀疲劳试验,研究了Nb微合金化对Cr-Co-Ni-Mo系超高强度不锈钢腐蚀疲劳性能的影响。结果表明,试验钢在3.5%NaCl溶液中具有一定的应力腐蚀敏感性,其应力腐蚀开裂机理为氢致开裂和阳极溶解的混合机制。Nb微合金化提高了钢的腐蚀疲劳性能,钢中添加0.11%的Nb后,钢的腐蚀疲劳强度由440 MPa提高至495 MPa,其主要原因是,Nb微合金化可以细化钢的晶粒尺寸,促进钢中不可逆氢陷阱NbC的析出,增加了钢中原奥氏体晶界总量、小角晶界所占比例、Σ3晶界数量、奥氏体体积分数等。 相似文献
2.
应变速率对管线钢在碱性溶液中应力腐蚀行为的影响 总被引:1,自引:0,他引:1
主要研究了不同应变速率对X70管线钢在库尔勒土壤模拟溶液中应力腐蚀行为的影响.采用慢应变速率拉伸实验(SSRT)研究了不同应变速率下X70管线钢在模拟溶液中应力腐蚀开裂行为,并利用扫描电镜分析了不同应变速率下的断面形貌.结果表明,应变速率(特别是局部应变速率)对X70管线钢在库尔勒土壤模拟溶液中应力腐蚀行为有重要影响,应变速率在5×10-7~5×10-6s-1之间有较强的应力腐蚀开裂敏感性,在裂纹扩展不同阶段氢和阳极溶解交互作用相对贡献大小不同. 相似文献
3.
预拉伸变形对Al-Cu-Mg合金腐蚀性能的影响 总被引:1,自引:0,他引:1
采用表面腐蚀、慢应变速率拉伸(SSRT)实验研究预拉伸变形对Al-Cu-Mg合金腐蚀性能的影响。利用扫描电镜观察分析Al-Cu-Mg合金断口形貌及结构。结果表明,预拉伸变形可显著提高合金位错密度,为H原子的扩散提供更多的通道,因此,在相同腐蚀时间下,3.5%NaCl溶液中T8态Al-Cu-Mg合金的腐蚀速率高于T6态。此外,预拉伸变形可显著增加S相弥散度,使得S相两侧的无沉淀析出带变窄,有效降低了晶界和晶内的电位差,从而降低晶界沉淀相的溶解速度,因此,在同一热处理状态下,Al-Cu-Mg合金在饱和H2S溶液中的应力腐蚀开裂敏感性高于干燥空气中的腐蚀开裂敏感性。同一应变速率下,T8态Al-Cu-Mg合金具有比T6态更好的抗应力腐蚀性能,表明预拉伸变形处理可显著提高合金的抗应力腐蚀性能。 相似文献
4.
对喷射成形7055铝合金分别进行T6时效和双级时效处理,然后在空气和3.5%NaCl溶液中进行慢应变速率拉伸实验,测定时效处理后合金的电导率,用扫描电镜观察合金的断口形貌。研究7055铝合金在T6及3种不同双级时效态下在空气和3.5%NaCl溶液中的应力腐蚀开裂行为。结果表明:7055铝合金只在一定的应变速率下应力腐蚀敏感性明显;相同时效制度下,4种应变速率(1.3×10 6,0.8×10 6,0.5×10 6和0.2×10 6s 1)中,应变速率为0.5×10 6s 1时应力腐蚀敏感性大;T6态合金的抗应力腐蚀性能最差,二级时效时间达到15 h后合金对应力腐蚀不敏感;应变速率为0.5×10 6s 1时,喷射成形7055铝合金的应力腐蚀断口的断裂方式为准解理断裂,在惰性介质中慢应变速率拉伸断口断裂方式为韧窝断口。 相似文献
5.
6.
在慢应变速率条件下,研究了Fe-Si-C系铁素体--马氏体双相钢焊接接头在人造海水中的应力腐蚀开裂行为,用单边预裂纹拉伸试样测定了焊接接头各部位的应力强度因子KI值。结果表明,焊接接头各部位在人造海水中的应力腐蚀开裂敏感性有很大差异,其中热影响区(HAZ)对SCC最敏感,K1值最低;随着阴极电位朝负方向增加,SCC敏感性增大;除氢处理可以改善焊接接头的SCC抗力。 相似文献
7.
利用腐蚀电化学法及化学浸泡法研究了1ONiCrMo钢在人工海水及3.5%NaCl溶液中的腐蚀行为.结果表明:1ONiCrMo钢在人工海水中的自然腐蚀电位为一0.690V,在3.5% NaCl溶液中为-0.661V,在人工海水中腐蚀电位较在3.5%NaCl溶液中低;3个月室内全、间浸腐蚀中,腐蚀速率大小主要受氧扩散控制影响,随着腐蚀时间增长,表面锈层的增厚,1ONiCrMo钢在人工海水及3.5%NaCl溶液中的全、间浸腐蚀速率随时间的延长而降低,1500h后趋向稳定;IONiCrMo钢在人工海水中全、间浸腐蚀速率分别为0.338~0.459mm/a和0.279~0.435mm/a,在3.5%NaCl溶液中全、间浸平均腐蚀速率分别为1.200~1.141mm/a和0.840~0.404 mm/a,虽在人工海水中腐蚀电位较在3.5%NaCl溶液中低,但在人工海水中全、间浸腐蚀速率均比对应时间段内在3.5%NaCl溶液中小,在人工海水中及3.5%NaCl溶液中的间浸腐蚀速率比全浸低. 相似文献
8.
利用腐蚀电化学法及化学浸泡法研究了10NiCrMo钢在人工海水及3.5%NaCl溶液中的腐蚀行为。结果表明:10NiCrMo钢在人工海水中的自然腐蚀电位为-0.690 V,在3.5%NaCl溶液中为-0.661 V,在人工海水中腐蚀电位较在3.5%NaCl溶液中低;3个月室内全、间浸腐蚀中,腐蚀速率大小主要受氧扩散控制影响,随着腐蚀时间增长,表面锈层的增厚,10NiCrMo钢在人工海水及3.5%NaCl溶液中的全、间浸腐蚀速率随时间的延长而降低,1 500 h后趋向稳定;10NiCrMo钢在人工海水中全、间浸腐蚀速率分别为0.338~0.459 mm/a和0.279~0.435 mm/a,在3.5%NaCl溶液中全、间浸平均腐蚀速率分别为1.200~1.141 mm/a和0.840~0.404 mm/a,虽在人工海水中腐蚀电位较在3.5%NaCl溶液中低,但在人工海水中全、间浸腐蚀速率均比对应时间段内在3.5%NaCl溶液中小,在人工海水中及3.5%NaCl溶液中的间浸腐蚀速率比全浸低。 相似文献
9.
研究14Cr-ODS、16Cr-ODS与310奥氏体钢在600℃/25 MPa的超临界水中的应力腐蚀开裂行为。通过慢应变速率拉伸实验得到应力-应变曲线,以及不锈钢的抗拉强度和伸长率。应力-应变曲线显示14Cr-ODS与16Cr-ODS都出现颈缩,而310奥氏体钢没有颈缩,达到极限强度后直接断裂,表现为脆性断裂特征。用扫描电镜对断口形貌进行观察,结果表明:16Cr-ODS的伸长率达到20%,断口成杯锥状,存在明显颈缩,但没有应力腐蚀开裂敏感性;14Cr-ODS断面上有韧窝出现,没有明显的应力腐蚀开裂敏感性;310奥氏体钢断裂方式几乎全为沿晶脆断,具有应力腐蚀开裂敏感性。 相似文献
10.
300M超高强度钢的应力腐蚀开裂 总被引:2,自引:0,他引:2
利用慢应变率拉伸试验技术研究了300M超高强度钢的应力腐蚀开裂(SCC),结果表明,300M钢在3.5%NaCl水溶液和蒸馏水中均对SCC敏感,随温度增加和拉伸应力变速率的降低钢的SCC敏感性增加,并且阴极极化和阳极极化均提高钢的SCC敏感性,除氧和降低溶液pH值均提高钢的SCC敏感性。 相似文献
11.
Initiation of stress corrosion cracking for pipeline steels in a carbonate-bicarbonate solution 总被引:1,自引:0,他引:1
The linearly increasing stress test (LIST) was used to study the stress corrosion cracking (SCC) behavior of a range of pipeline
steels in carbonate-bicarbonate solution under stress rate control at different applied potentials. Stress corrosion cracking,
at potentials below -800 mV(SCE), was attributed to hydrogen embrittlement. Stress corrosion cracking, in the potential range
from about-700 to -500 mV(SCE), was attributed to an anodic dissolution mechanism. In the anodic potential region, the SCC
initiation stress was larger than the yield stress and was associated with significant plastic deformation at the cracking
site. The relative SCC initiation resistance decreased with in-creasing yield strength. In the cathodic potential region,
the SCC initiation stress was smaller than the yield stress of steel; it was approximately equal to the stress at 0.1 pct
strain(@#@ Σ0.1pct) for all the steels. The original surface was more susceptible to SCC initiation than the polished surface. 相似文献
12.
The stress corrosion cracking (SCC) behavior of PH13-8Mo precipitation hardening stainless steel (PHSS) in neutral NaCl solutions was investigated through slow-strain-rate tensile (SSRT)test at various applied potentials.Fracture morphology,elongation ratio,and percentage reduction of area were measured to evaluate the SCC susceptibility.A critical concentration of 1.0mol/L neutral NaCl existed for SCC of PH13-8Mo steel.Significant SCC emerged when the applied potential was more negative than-0.15 VSCE,and the SCC behavior was controlled by an anodic dissolution (AD) process.When the applied potential was lower than-0.55 VSCE,an obvious hydrogen-fracture morphology was observed,which indicated that the SCC behavior was controlled by hydrogen-induced cracking (HIC).Between-0.15 and-0.35 VSCE,the applied potential exceeded the equilibrium hydrogen evolution potential in neutral NaCl solutions and the crack tips were of electrochemical origin in the anodic region;thus,the SCC process was dominated by the AD mechanism. 相似文献
13.
The role of hydrogen in stress-corrosion cracking (SCC) of austenitic stainless steel was investigated in boiling chloride
solution. The tests in the mixed melted salt verified that hydrogen-induced cracking (HIC) could occur at 160 °C if sufficient
hydrogen could be supplied continuously. It was found that the threshold SCC intensity factors of both 321 and 310 steels
were lower than those of HIC during dynamic charging at high fugacity at 40 °C and 160 °C. In addition, anodic polarization
decreased hydrogen concentration and promoted SCC in hot LiCl solution, while cathodic polarization increased hydrogen concentration
and restrained SCC. Hydrogen could be introduced into the specimen and be concentrated at the crack tip during SCC. It could
promote anodic dissolution and SCC remarkably, although it was not enough to produce cracking. 相似文献
14.
《Acta Metallurgica Materialia》1991,39(11):2597-2605
The stress corrosion cracking (SCC) susceptibility of two aluminum-lithium alloys, a binary AlLi and a ternary AlLiCu alloy, in 0.5 M NaCl solution was investigated using the constant elongation rate technique (CERT). Susceptibility increased with decreasing strain rate and with aging. The alloys were susceptible under both anodic and cathodic applied potentials. The susceptibility dependence of the alloys as a function of applied potential correlates well with published hydrogen permeability data. The susceptibility increased dramatically when hydrogen was charged into the specimen using a hydrogen re-combination “poison” during CERT testing. These experiments suggest that hydrogen plays a major role in the SCC of these alloys. A brittle hydride having the composition LiAlH4 forms in the AlLi system under conditions of severe SCC susceptibility. The brittleness of the hydride is explained. The formation of the hydride is a sufficient condition for SCC of AlLi alloys. A process of SCC in AlLi alloys is proposed wherein hydrogen causes damage by the formation of a hydride. 相似文献
15.
Corrosion fatigue crack growth rates were measured on compact toughness specimens of ASTM A-471 turbine disc steel in room
temperature 12M NaOH solution. The role of cathodic potentials on corrosion fatigue crack growth rates was investigated. Intergranular
cracking was observed at cathodic potentials compared to transgranular cracking at open circuit potential and in air. The
results suggest a hydrogen embrittlement mechanism of cracking at cathodic potentials. The results suggest that hydrogen diffusion
into the material ahead of the crack tip is not rate controlling but is a necessary condition to accelerated cracking. Positive
and negative sawtooth wave form results show that environmental effects are accelerated during loading part of the cycle when
deformation is occuring. The results have also been analyzed with respect to the linear superposition model proposed by Wei
and Landes.
R. RUNGTA formerly with The Ohio State University, Columbus, OH.
J. A. BEGIEY formerly with The Ohio State University, Columbus, OH. 相似文献
16.
LI Hui-lu GAO Ke-wei QIAO Li-jie WANG Yan-bing CHU Wu-yang HUI Wei-jun DONG Han WENG Yu-qing 《钢铁研究学报(英文版)》2001,8(2):42-46
Stress corrosion cracking (SCC) of highstrength steels in an aqueous solution has been wide-ly investigated[1— 8] .It has long been accepted thatSCC of high strength steel in water is one kind ofhydrogen- induced cracking (HIC) [1— 5] .Because ofhydrolysis of the metal ions,the value p H of the lo-cal environment within a pit,crevice or crack on asteel surface can be decreased to about 3.5 [1] .Be-cause of crack- tip acidification,local conditions arealways favorable for release of hydro… 相似文献
17.
Denny A. Jones 《Metallurgical and Materials Transactions A》1985,16(6):1133-1141
A mechanism of stress corrosion cracking (SCC) is outlined in which anodic dissolution at film rupture sites relieves strain
hardening and reduces the fracture stress at the crack tip. Experimental evidence is cited to suggest that relief of strain
hardening occurs by interaction of subsurface dislocations with divacancies generated by the anodic dissolution. A transgranular
crack propagates by accumulation of divacancies on prismatic planes which then separate by cleavage under plane strain conditions
at the crack tip. At appropriate metallurgical and chemical conditions, anodic dissolution and/or divacancy migration may
be enhanced at grain boundaries, leading to an intergranular failure mode. Evidence is also available to indicate that cyclic
loading relieves strain hardening. Relief of strain hardening by combined cyclic loading and corrosion accounts for the higher
incidence of corrosion fatigue cracking (CFC) without the requirement of any critical dissolved species. Data on fatigue of
stainless steel at elevated temperature in both vacuum and air provide additional support for the proposed mechanism. 相似文献
18.
Stress corrosion cracking of an Al-Li alloy 总被引:1,自引:0,他引:1
Z. F. Wang Z. Y. Zhu Y. Zhang W. Ke 《Metallurgical and Materials Transactions A》1992,23(12):3337-3341
Stress corrosion cracking (SCC) has been studied in an Al-Li alloy with variables of orientation of specimen, heat treatment,
and applied potentials. The distribution of the electrochemical potential resulting from precipitate clusters was measured,
and the hydrogen content on the specimen surface was detected. The results showed that the SCC susceptibility under the peakaged
(PA) condition was higher than that under the natural (NA) and overaged (OA) conditions. The transverse (TL) specimen was
more susceptible to SCC propagation than the longitudinal (LT) specimen. The SCC susceptibility and the hydrogen content on
the specimen surface were dependent on the applied potentials. The hydrogen content increased when the applied potential changed
to positive or negative directions. There was a critical hydrogen content, below which local anodic dissolution (LAD) plays
an important role, above which hydrogen embrittlement (HE) plays an important role. 相似文献
19.
Wang Z. F. Zhu Z. Y. Zhang Y. Ke W. 《Metallurgical and Materials Transactions A》1992,23(1):3337-3341
Stress corrosion cracking (SCC) has been studied in an Al-Li alloy with variables of orientation of specimen, heat treatment, and applied potentials. The distribution of the electrochemical potential resulting from precipitate clusters was measured, and the hydrogen content on the specimen surface was detected. The results showed that the SCC susceptibility under the peak- aged (PA) condition was higher than that under the natural (NA) and overaged (OA) conditions. The transverse (TL) specimen was more susceptible to SCC propagation than the longitudinal (LT) specimen. The SCC susceptibility and the hydrogen content on the specimen surface were dependent on the applied potentials. The hydrogen content increased when the applied potential changed to positive or negative directions. There was a critical hydrogen content, below which local anodic dissolution (LAD) plays an important role, above which hydrogen embrittlement (HE) plays an important role. 相似文献