023-86669155
李志义1,2,马学文3,李晓澎1,2
(1.重庆义扬机电设备有限公司,重庆 400042; 2.重庆长江工业炉公司, 重庆 401329; 3.株州齿轮公司,湖南 株州 400029)
前言:当我们去有关兄弟工厂和学术交流的时候,不少同志询问我们关于气体渗碳淬火件中的氢脆问题,由于在重庆296厂主持兵器用结构钢在表面处理过程中氢脆和应力腐蚀断裂的研究 该项目由重庆296厂李志义、姜相荣、袁纪良,包头52所王来生、王明美、厉小东等高工、清华大学顾家琳教授、中科院沈阳金属研究所王毓麟研究员和杜金山高工共同完成,首创145℃高温浓碱介质中悬臂弯曲试验,系统地测试了十种钢在不同表面处理方法及不同工艺规范下材料的缺口强度和应力腐蚀门槛应力强度因子,同时测定上述钢的氢行为,包括吸氢量、氢扩散系数、氢逸出规律、电化学特性、检测氢与某些元素的交互作用,宏观和微观断口分析等),经7312个试样8年研究获部级二等奖,该项技术属国内首例,对于机械行业产品失效分析具有重要的指导作用。对有关渗碳淬火件的氢脆总是也只有一览而已……。如今退休16年了,也没有精力并综述并深入研究。为此将我们的研究体会交流给大家,望大家能有收获。
摘要:阐述了氢塑、氢脆现象,特别是气体渗碳件的氢脆、硫脆、汞脆问题。气体渗碳件中的进氢量与渗碳工艺和合金元素种类及含量等因素有关。提出了有关氢脆和白点的一些新观念。指出,气氛中高含硫量(包括有机硫和无机硫)也是造成渗碳件氢脆的主要原因之一。此外,还论述了氢陷阱及降低气体渗碳淬火件氢脆的某些要点。
关键词:气体渗碳;氢脆;氢塑;硫脆、汞脆;氢陷阱
Research of Hydrogen Brittleness in Gas Carburizing & Quenching Pieces
Li Zhiyi1,2, Ma Xuewen3, Li Xiaopeng1,2
(1. Chongqing Yiyang Electromechanical Equipment co., ltd Chongqing 400042;
2. Chongqing Yangtze Industrial Furnace Company Chongqing 401329;
3. Zhuzhou Gear Company Hunan Zhuzhou 400029)
Introduction:So many people asked us some questions about the Hydrogen brittleness in gas carburizing-quenching pieces when we visited other relative factories or made academic exchanges, because we have made deep research in Hydrogen brittleness and stress corrosion fracture in structural steel for weapons with surface treatment. The research was completed by the senior engineers of Li Zhiyi, Jiang Xiangrong, Yuan Jiliang, working in Chongqing 296 factory, and Wang laisheng, Wang Mingmei, Li Xiaodong, working in 52 research institute in Paotou, and Pro. Gu Jialin in Tsinghua University, and research fellow Wang Yulin, Du jinshan in Academia Sinic Shenyang Institute of Metal Research. Cantilever bending test was succeeded firstly in high temperature concentrated alkali medium at 145℃. And the notch strength and stress corrosion critical stress intensity factor were tested systematically in 10 types of steels which were different in ways and process specifications of surface treatment. The behaviors of hydrogen (including capacity of hydrogen absorption, diffusion coefficient of hydrogen, escape regularity of hydrogen, electrochemical character, test of interaction between hydrogen and some other element, and macro- and micro-fracture analysis ) in the steels were tested simultaneously. This technology, which has been obtained the second prize of ministry-level, and also which is the first one in China, was worked over 8 years and researched through 7,312 samples. It is placed an important role on failure analysis of product in mechanical industries. The researches of the hydrogen brittleness in carburizing & quenching pieces are always so few……. Now I have been retired for 13 years, and I am too tired to research deeply. So we just give you some experiences of our research, I hope that it will be helpful to you.
Abstract: The plastic hydrogen, hydrogen embrittlement phenomenon, especially in gas carburizing parts hydrogen embrittlement problems. Gas carburizing conditions in the amount of hydrogen into the carburizing process and with the type and content of alloying elements and other factors. Proposed hydrogen embrittlement and white flake on some new ideas. That the atmosphere in the high sulfur content (including organic sulfur and inorganic sulfur) also contributed to the carburizing one of the main pieces of hydrogen embrittlement. In addition, discusses the pitfalls and reduce the hydrogen gas carburized parts hydrogen embrittlement of certain points.
Key word: gas carburizing; hydrogen embrittlement; hydrogen plastic; Brittle sulfur, mercury brittle;hydrogen trap
1. 氢进入金属中二大性能:氢脆性和氢塑性
即氢脆和氢塑,在一定条件下,氢进入金属中使塑性增加称氢塑,反之为氢脆。
低温氢塑是苏联人65年发现,他们在研究液氢使用于空间运载火箭燃料和原子能核裂变冷却液的前期工程中研究在-200℃以下时,载氢体金属材料出现氢塑现象。
高温氢塑于70年美国人研究Ti合金时发现并发表在杂志上。实际上苏联人早几年前研究Ti合金用于超音速3倍以上的飞机上,已用于实践,只因军事秘密没有对外公布而已……。
在常温下金属中的氢只表现为氢脆现象。
2.气体渗碳淬火件在目前条件,在气体渗碳中还没有不渗氢的渗碳方法……。因此渗碳过程中必然伴随有渗氢的过程……。
2.1在高温气体渗碳中伴随有渗氢的过程,进氢量与工艺有关。
一般讲:周围环境氢含量越高,越易进氢,这就解释了为什么同一型号钢种同一有效硬化层深条件下在吸热式气氛中通氨的C-N共渗比不通氨的单一渗碳、渗氢量高。同样供碳量下,氢量越多,渗氢量越多,例如:CH4与C3H8两种气源在同样含水、含硫、含汞条件下比较。当然天然气渗氢量相对多一些。时间越长进氢量越多。
2.2进氢量与化学成份的关系详见[1]
2.2.1增加氢脆敏感性的元素:硼、磷、硫、铝、镍
2.2.2减少氢脆敏感性的元素:铈和其它稀土元素
(1)他们的吸氢作用,防止了白点的形成
(2)添加镧能净化其它的普通残质,La2O2S,La2Sn,LaP。使晶界净化,使回火脆性的杂质不易向晶间偏聚形成稳定的氢陷阱或稳定的氢化物,使氢不易向应力方向迁移和扩散,减少在应力作用下的氢的偏聚能力,而降低了氢脆性。
(3)促进回火脆性的杂质元素均是促进氢脆的元素。
2.2.3结构硼钢(国军标GJB2720-1996)经我们生产实践和实际生产试样的研究[6、7],确实氢脆敏感性增加,当我们委托复旦大学采用法国CAMECE公司制造的“IMS3F型离子探针”,测试发现H与B是相互排斥的,见图1、2、3,而在阳线上编号870926007、870926006、870926005反映不明显。但从图1、图2、图3可见B在钢中的分布是不均匀的,明显地显示出波峰和波谷。即不存在因硼氢化物的形成而增加了硼钢的氢脆性。这对硼钢的氢脆机理有待新的考证……。同时也验证氢与铁、氢与铬之间不形成化合物。同时也看出,镀硬铬层氢含量低。
50BA钢中氢与某些元素的交互作用:图1、图2、图3
Hydrogen in 50BA steel with certain elements of the interaction: Figure 1, figure 2, figure 3
注:试样是采用自动步枪、枪管(50BA材料):镀硬铬、超深冷-196℃、密封空运至上海复旦大学曹永明教授检测,详见重庆义扬机电设备有限公司网站:氢与某些元素的交互作用。
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