共查询到18条相似文献,搜索用时 356 毫秒
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对于一些长期在中温条件下服役的Cr-Mo钢(2.25Cr1Mo),由于钢中P、S等有害杂质元素在服役过程中不断向晶界偏聚,降低了晶界结合力,致使该类钢出现第二类回火脆性这一关键问题。为了探寻降低这类Cr-Mo钢第二类回火脆性倾向的有效方法,提高材料安全服役可靠性,从溶质元素偏聚机制出发,总结分析了合金元素晶界偏聚及改善钢第二类回火脆性的内在本质,重点归纳了几种常见元素的晶界偏聚行为及其对钢回火脆性的影响,同时还客观分析了理论计算和试验研究在阐释合金元素对晶界脆性影响存在差异的主要原因,期望能为中温用钢长期服役过程中存在的回火脆性提供一些有效控制方法,也为合金元素晶界偏聚行为的研究提供一些参考。 相似文献
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对于Cr-Mo低合金钢断裂韧性的敏感性有相反的结论报导,因此,有必要进二步研究说明产生相反结论的原因。本研究通过对3Cr-1Mo和2.25Cr-1Mo2种类型钢的断裂韧性的变化,观测其产生的原因,合理解释产生相反结论的原因。为研究钢的脆化敏感性,使用了一个J因素,因为有高J因素的Cr—Mo低合金钢对回火脆性较敏感。对于这些合金的感应回火脆化,采用了从高温到室温一个周期234h的分段冷却工艺。对脆性合金和非脆性合金的某些机械性能进行了检测和对比,结果表明,分段冷却工艺对抗拉强度和硬度没有显著影响,但对冲击抗力影响很大。 相似文献
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大型锻件用钢的回火脆性 总被引:3,自引:0,他引:3
讨论了回火脆性的产生原因和合金元素及杂质对钢的回火脆性的影响,介绍了目前国际上测定与判别回火脆性的方法,几种典型大锻件有钢的回火脆化倾向以及这种脆化倾向的工艺途径。 相似文献
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钢的回火脆性钢的回火脆性(与回火后钢的冷却条件有关的脆性),这一个题目,在解决制造业中使用不含钼钢材的问题上,特别迫切,一直到现在,很多研究还是说,没有一种无钼钢,不是倾向于形成回火脆性的。实际上,成品回火后,是快速冷却的话,无钼钢是保证能用的。可是有很多成品,要求具有最小的残余应力(旋转轴,透平机叶,挖掘机轴等等);而为了要制作这些成品,就必需寻求:没有回火脆性倾向 相似文献
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对ML20MnVB钢在不同热处理制度下的力学性能和低温脆性转变温度进行了试验研究。试验结果表明,该钢的σ0.2和σ随回火温度升高而降低δ和ψ随回火温度升高而增加,而且当回火温度高于400℃时,其σ0.2和σb急剧降低,但δ和ψ无急剧变化,该钢的低温回火脆性温度区在250℃附近。该钢的低温脆性转变温度为-48℃。 相似文献
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回火温度对30CrMnSiNi2A钢组织和性能的影响 总被引:7,自引:0,他引:7
在200-300℃温度范围内30CrMnSiNi2A钢ε-碳化物稳定性和残余奥氏体的热稳定性较好。因此200-300℃回火均可保持稳定力学性能,并随回火温度的提高钢的屈服强度σ0.2提高。30CrMnSiNi2A钢在400-550℃回火时出现了明显的回火脆性。 相似文献
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本文就合金元素钼对40Si2Mn2钢回火马氏体脆性(TME)的影响作了研究。试验结果表明钼不能消除40Si2Mn2钢的TME,但可以降低钢的韧性脆性转变温度(DBTT),从而使显示钢的TME的冲击试验温度降低;再有,钼可以提高40Si2Mn2钢TME出现的回火温度,即钼对钢的TME具有推迟作用,透射电镜观察的结果表明钼的这一作用与钼阻碍钢在回火过程中渗碳体(Cem)的析出有关。 相似文献
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T. Ogura 《Metallurgical and Materials Transactions A》1982,13(12):2205-2207
The temper embrittlement equation of a P-doped NiCr steel and the McLean’s equation for equilibrium intergranular segregation
of P in the same steel were derived experimentally. On the basis of these equations, two-dimensional temper embrittlement
diagrams were constructed. It was shown that the construction of a temper embrittlement diagram offers a way to predict the
ultimate level of temper brittleness of steels. 相似文献
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The kinetics of isothermal temper embrittlement have been studied in a 3 pet Cr-Mo turbine disc steel at tempering temperatures from 450 to 580‡C. In the cast examined embrittlement results principally from the segregation of phosphorus to prior austenite grain boundaries and it is shown that the present results are consistent with an equilibrium segregation process. These data have been used to predict the degree of embrittlement resulting from continuous cooling from the tempering temperature and the results have been compared with laboratory tests for a wide range of cooling rates. The probable effect of post-tempering cooling rate on toughness and the feasibility of using retempering treatments as a means of rehabilitating temper embrittled components are also considered. 相似文献
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B. L. King und G. Wigmore 《Metallurgical and Materials Transactions A》1976,7(10):1761-1767
The kinetics of isothermal temper embrittlement have been studied in a 3 pet Cr-Mo turbine disc steel at tempering temperatures
from 450 to 580‡C. In the cast examined embrittlement results principally from the segregation of phosphorus to prior
austenite grain boundaries and it is shown that the present results are consistent with an equilibrium segregation process.
These data have been used to predict the degree of embrittlement resulting from continuous cooling from the tempering temperature
and the results have been compared with laboratory tests for a wide range of cooling rates. The probable effect of post-tempering
cooling rate on toughness and the feasibility of using retempering treatments as a means of rehabilitating temper embrittled
components are also considered.
相似文献
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《钢铁研究学报(英文版)》2011,(Z1):898-902
Based on the phenomenon of brittle fracture occurred during tensile test for 20Mn2A high strength circular chain used in coal mines,the fracture property is regarded as intercrystalline brittle one after macroscope observation and metallographic examination.It is analysed that the intercrystalline brittle fracture is due to high tempering temperature and limited processing site where final products are piled together after heat treatment,which lead to a lower cooling rate of internal chain,with Si,Mn and P etc elements segregating and enriching in the austenite grain boundary and forming high tempering brittleness.After these circular chains are tempered again for one hour at 670℃,and oil-cooled rapidly,due to the reversibility of high temper brittleness for structural alloy steel,the high temper brittleness can be eliminated and products are completely qualified after tensile inspection. 相似文献