X65管线钢抗氢致开裂性能研究

研究了4个批次X65管线钢抗氢致开裂(HIC)性能,结果表明,试样经硫化氢腐蚀试验后,表面均出现了氢鼓泡,但裂纹敏感率不同。X65管线钢C、Mn含量较低、Cu含量较高时,裂纹敏感率较低。当X65管线钢组织存在偏析带时,氢致裂纹在偏析带上起源,并沿偏析带扩展。     

450 MPa级海底管线钢HIC试验裂纹分析研究

H₂S腐蚀问题在油气输送过程中十分重要，其破坏性和危害性极大，严重影响了油气输送管道的寿命，制约了油气输送管道材料的发展，因此抗H₂S腐蚀管道用钢成为其中一种发展趋势。本文采用经济型成分设计，开发出450 MPa级耐酸性海底管线钢，但HIC试验出现轻微的氢致裂纹。通过金相显微镜、扫描电镜、EDS等手段，分别对试验钢在HIC试验中产生裂纹的原因，从组织、杂物、元素偏析、硬度等方面进行分析研究，找出HIC试验出现裂纹的原因，来提高450 MPa级海底管线钢的耐HIC性能。研究结果表明：HIC试验中出现的裂纹不是由钢中异常夹杂物造成的，而是由于钢中的Mn偏析产生了硬相的微观组织引起的。     

T/S25k钢板拉力试样分层原因探讨

本文对T/S25K钢卷分层缺陷问题,进行了超声波探伤、金相分析以及抗H_2S试验,微观分析夹杂物种类较多,显微组织为铁素体和珠光体,珠光体量各试样相差悬殊,板厚中部可见碳、硫、磷偏析,分层沿成分偏析延伸。钢板中大量夹杂物和低倍缺陷的存在严重影响了钢板的使用性能。抗H_2S浸蚀试验表明,该钢板极易产生氢鼓包和氢致裂纹,若长期在H_2S腐蚀条件下使用,将会产生严重的坑蚀和阶梯状裂纹,以致引起钢管破裂事故.     

国内外高强度管线钢专利技术研发进展

根据2011年国内外公布的高强度管线钢-平板、热轧板卷和无缝管的专利制造技术,概述了抗大变形、优良低温韧性、耐腐蚀性管线钢的关键技术、组织和性能高强度管线钢研发特点和趋势主要有:抗大变形管线钢-通过组织中弥散的M/A组元提高钢的强度:低温韧性钢-采用Mn-Nb-Mo合金化,通过控制轧制获得铁素体和/或贝氏体为主的组织:抗HIC(氢致裂纹)管线钢-控制C,P、Mn偏析引起的HIC的前提下,降低Nb,Ti含量,防止因Nb、Ti碳氮化物引起的氢致开裂.     

X70MS管线钢抗HIC性能研究

X70MS管线钢主要用于输送含有H₂S等酸性介质的石油和天然气,由于其特殊的服役环境,因此需要管线钢具有非常良好的抗HIC性能。为了降低X70MS管线钢的HIC敏感性,提高其服役安全性,采用NACE TM 0284-2016氢致开裂标准试验方法,对X70MS管线钢的抗HIC性能进行了研究。结果表明：X70MS管线钢的组织为铁素体、贝氏体以及M/A岛;HIC试验中,裂纹的各个指标参数均符合国内西气东输工程用X70管线钢评定标准的要求,具有良好的抗HIC性能;HIC裂纹是由Al₂O₃夹杂物以及铸坯中C元素偏析遗传到钢板中形成大块状的M/A岛富碳组织所致,Al₂O₃夹杂物与M/A岛组织相互间的耦合作用会加剧X70MS管线钢抗HIC性能恶化,并且M/A岛组织数量、分布、尺寸是影响X70MS管线钢抗HIC性能的重要因素。     

X65 M管线钢抗HIC性能分析与生产实践

针对在H2S含量偏高特殊环境下使用的X65M管线钢产品抗氢致裂纹(HIC)进行了分析与研究。通过对化学成分、元素偏析、非金属夹杂物对抗氢致裂纹影响的机理分析,指导冶炼过程硫、磷、氢及氧化夹杂物等关键工艺控制,并通过连铸过程严格的保护浇铸措施,实现了钢水w[S]0.002%,w[P]0.010%,w[H]2.0×10-6,钢中各类夹杂物小于1.0的控制水平。X65M管线钢抗氢致裂纹检测符合产品开发标准要求。     

X70管线钢抗氢致开裂性能研究

研究了4个批次X70管线钢抗氢致开裂(HIC)性能,结果表明,经硫化氢腐蚀试验后,试样表面均出现了氢鼓泡,仅A177批次出现氢致裂纹。试样内部夹杂物以及微观组织偏析导致了氢致裂纹的产生和生长。试样表面存在的硫化物和氧化钙夹杂物是导致氢致鼓泡产生的重要原因。     

中心偏析对厚板层状撕裂的影响

在厚钢板的使用中,层状撕裂、氢诱发的裂纹发生在中心偏析组织。这些组织中的Mn、P偏析量及硬度影响着氢诱发裂纹的敏感性。虽然研究了偏析的硬度与Mn、P、C偏析量之间的关系,但还不能明确地说出裂纹在中心偏析组织发生的临界条件。 本文报导的是对50公斤级钢中发生层状撕     

100 t BOF-LF-VD-CC流程抗硫管线钢KS30的生产实践

抗硫管线钢主要用于加工石油、天然气的输送管道,对钢的强度、韧性、抗氢致裂纹(HIC)、抗硫应力腐蚀裂纹(SSC)和焊接性能等要求很高。结合石钢京诚生产抗硫管线钢的生产实践,对各成分的作用及影响进行了分析,并对抗硫管线钢KS30生产实践进行了介绍。在铁水P含量≤0.120%、铁水S含量≤0.050%的情况下,优选原辅料,可保证抗硫管线钢KS30成品P含量≤0.010%、S含量≤0.0015%、O含量≤0.0012%,轧材抗HIC、抗SSC性能全部合格     

影响管线钢氢致开裂敏感性的因素分析

对几种不同材质、不同规格的钢材在含饱和H2S的人工海水中的氢致开裂（H IC）行为进行了试验分析。结果表明,钢材中Mn、P、S含量高时,易在中心造成成分偏析带,带状组织严重,MnS夹杂增多,是H IC敏感性能升高的主要因素。     

Effect of Microstructure on Hydrogen Induced Cracking Behavior of a High Deformability Pipeline Steel

The hydrogen induced cracking(HIC) behavior of a high deformability pipeline steel was investigated with three different dual-phase microstructures,ferrite and bainite(F+B),ferrite and martensite/austenite islands(F+M/A) and ferrite and martensite(F+M),respectively.The HIC test was conducted in hydrogen sulfide(H2S)-saturated solution.The results showed that the steels with F+B and F+M/A dual-phase microstructures had both higher deformability and better HIC resistance,whereas the harder martensite phase in F+M microstructure was responsible for the worst HIC resistance.The band-like hard phase in dual-phase microstructure was believed to lead to increasing susceptibility to HIC.     

Resistance of Trip 800 Steels in a Sour Environment Containing H2S

We have evaluated the resistance of two samples of TRIP 800 steel prepared under laboratory conditions at the Faculty of Metallurgy and Materials Engineering (FMME) V?B (Technical University of Ostrava, Czech Republic) in a sour environment containing H₂S. The first steel investigated had a C–Mn–Si composition, and the second steel had a C–Mn–Si–Al composition. Both TRIP steels were characterized using the yield strength in the range 420 to 450 MPa and tensile strength in the range 880 to 900 MPa. The TRIP steel samples were in the form of sheets with a thickness of 1.5 mm. The residual austenite content was 11% and 13%, respectively, in the two steels studied. The resistance to hydrogen embrittlement was evaluated in a sour environment that contained hydrogen sulphide using hydrogen‐induced cracking (HIC) and sulphide stress cracking (SSC) tests performed in accordance with NACE standards. Both TRIP 800 steels showed a high resistance to hydrogen embrittlement, and no SSC cracks were observed. Some cracking arising from HIC was observed in both steels. The measured parameters showed some variation; in some cases they were lower than recommended limits, but in other cases the measured parameters were higher (e.g., the crack length ratio was up to 70%). The cracks initiated preferentially at non‐metallic inclusions, either at elongated manganese sulphide particles, or at oxide stringers that were rich in Al.     

轧制工艺对X70耐酸管线钢抗HIC和力学性能的影响

研究了终轧温度和在线冷却方式对X70级耐酸管线钢力学性能和抗HIC性能的影响。结果显示:层流冷却相对于在线空冷,钢板的强韧性有明显提高,两种工艺下钢板的硬度指标相当;在相同冷却工艺下,提高终轧温度有利于屈服强度和抗拉强度的提高;抗HIC性能只与铸坯质量有关,与轧制工艺、组织状态、晶粒度大小无关。根据研究的结果进行了X70级别耐酸管线钢的工业试制,所得X70管线钢在强韧性满足标准要求的前提下,保持了良好的抗HIC性能。     

镁处理对海底管线钢氢致开裂敏感性和氢捕获效率影响

通过NACE TM 0284-2016标准试验和Davanathan-Stachurski双电解池氢渗透试验,评估和分析了不同镁添加量X70级别海底管线试验钢的氢致开裂(HIC)敏感性和氢捕获效率.结果表明,镁处理可以细化钢中夹杂物,形成以Ti2O3为主要成分的复合夹杂物.随着镁添加量的增加,试验钢的晶粒依次细化,虽然...     

高洁净度管线钢中元素的作用与控制

论述了石油,天然气输送用管线钢中碳,氧,硫,磷,氢,锰等元素的作用与控制技术,尤其是各元素对HIC的影响,可为生产高洁净度管线钢的工艺选择和成分控制提供参考。     

宝钢管线钢的发展回顾

文章回顾了过去15年间宝钢管线钢的发展.通过对高强度高韧性管线钢、具有抗HIC性能管线钢和大口径输气管线用厚规格的针状铁素体型X70管线钢的研究开发,形成宝钢X系列管线钢的成分和工艺体系.产品质量稳定,已批量应用于西气东输管线工程、忠武输气管线工程、土耳其输气管线工程等国内外重要管线工程.     

焊接匹配及合金元素对国产管线钢腐蚀的影响

采用恒载荷拉伸法，测试了国产管线钢母材及其焊接接头的硫化物应力腐蚀开裂SSCC性能。结果表明：焊接匹配、合金元素是影响国产管线钢SSCC的重要因素。不同的焊接匹配将导致管线钢具有不同的耐腐蚀性能；不同碳、锰、磷含量的的国产管线钢在相同试验条件下具有不同的SSCC断裂时间与断裂应力，该试验结果主要是由于它们的Mn、P元素含量不同引起的，而不是C元素。     

L245钢抗SSC、HIC的性能试验

采用NACETM0284—2003和NACETM0117—2005实验方法对L245钢进行评定。结果表明：在湿心S环境下,L245钢具有良好的抗氢致开裂（HIC）和硫化氢应力腐蚀（SSC）的能力。在试验结果基础上,对其腐蚀机理及影响因素进行了讨论。     

Effect of Ultra Fast Cooling on the Alloy Cost Reduction of the X80 Pipeline Steel

The microstructures and mechanical properties of X80 pipeline steels produced by both novel ultra fast cooling and conventional‐accelerated continuous cooling modes are investigated. Results showed that different levels of Mo addition had a remarkable effect on the microstructures and mechanical properties of the investigated pipeline steels. The proeutectoid ferrite and pearlite formation is inhibited in the high‐Mo steel and acicular ferrite is obtained over a wide range of cooling rates, whereas the dominant acicular ferrite microstructure can only be obtained when the cooling rates reach up to 5 C s^?1. Very similar microstructures and mechanical properties are obtained in the low‐Mo steel produced with ultra fast cooling and in the high‐Mo steel produced by the conventional‐accelerated continuous cooling. It was proved by simulation and industrial trials that high‐strength low‐alloy steels such as pipeline steels, can be produced using the novel ultra fast cooling which also reduce alloy cost.

     

Effect of silicon on the wear resistance of high-carbon steels with the structures of isothermal decomposition of austenite during friction and abrasive action

The hardness and wear resistance during sliding and abrasive friction of 80S2 (0.83% C, 1.66% Si) and U8 (0.83% C) steels subjected to the isothermal γ → α decomposition in the temperature range 330–650°C and additional 5-min annealing at 650°C are compared. The optimum decomposition temperature is found to be 550°C. At this temperature, fine lamellar pearlite with the maximum hardness and wear resistance as compared to other pearlitic and bainitic structures forms in the silicon steel. The silicon-alloyed fine lamellar pearlite of 80S2 steel is found to have high hardness and abrasive wear resistance as compared to the similar structure in plain U8 steel; however, this pearlite has no advantages in the wear resistance under conditions of sliding friction on a steel plate. Silicon alloying of the bainitic structures in the eutectoid steel leads to a noticeable decrease in the wear resistance during sliding friction and abrasive action. Friction oxidation is shown to negatively affect the abrasive wear resistance of the silicon steel.