共查询到19条相似文献,搜索用时 78 毫秒
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采用恒温有限元法,研究了一定温度与氢原子回火脆化对三种不同成分2.25Cr-1Mo钢局部脆断应力的影响,结果发现,可用局部脆断应力σ1的变化衡量材料的回火脆化倾向,但由于晶界上杂质元素与氢原子分布的随机性,可能导致沿晶脆断应力的分析,在降低局部脆断应力的作用下,氢脆与回火脆化具有叠加关系。 相似文献
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Machinability of medium carbon tin- bearing free cutting steel 总被引:1,自引:0,他引:1
Tin- bearing free cutting steel is environmentally friendly material. The test steel of 100mm in diameter with Sn of 0. 16 mass% by smelting in industrial frequency induction furnace and hot forging was prepared. Machinability experiments of the test steel using a stepless speed regulation lathe(C6140) was conducted. Besides, the distribution of tin, sulfur and manganese in the tested steel using secondary ion mass spectrometer was analyzed. The research results show that the coefficient of relative machinability of the test steel is 1. 75, the style of cutting chip mainly is C- shaped, in addition to this, there is a small amount of helical chip. Therefore, the test steel has excellent machinability, and it can meet the requirements of high speed machining. It is considered that grain boundary embrittlement caused by segregation of tin at ferrite grain boundaries, liquid metal embrittlement and lubrication action caused by low melting point of tin, are main reasons of the improvement of machinability. 相似文献
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以含Bi和不含Bi两种成分低温取向硅钢进行高温退火中断实验,借助磁测仪(MPG 200D)进行磁性能测量,借助金相显微镜观察晶粒尺寸,利用X射线衍射(XRD)对高温退火连续升温过程中织构进行研究分析。实验结果表明,添加Bi元素后,初次晶粒尺寸减小,二次再结晶晶粒尺寸增加至20~60 mm,成品磁性能更优。Bi加入后二次再结晶开始温度明显提高,含Bi试样和不含Bi试样发生晶粒异常长大的温度范围分别是1 080~1 100 ℃和1 060~1 080 ℃。织构分析结果显示,随着高温退火温度提高,{111}和{100}面织构逐渐减弱,{110}面织构和Goss织构逐渐增强,含Bi和不含Bi试样的高斯织构转变温度分别为1 100 ℃和1 080 ℃,随后高斯织构密度和体积百分比逐步增加,最终含Bi试样的高斯织构密度和体积百分比均高于不含Bi试样。 相似文献
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通过SEM、TEM、XRD、化学相分析等方法对比研究新型扭杆弹簧用40Si2Ni2CrMoV钢(代号N1)和现有45CrNiMoVA钢微观组织及其对力学性能的影响,并利用慢应变速率拉伸方法对比研究两种不同扭杆弹簧用钢的氢脆敏感性。结果发现,N1钢由于添加硅、钼等抗回火软化元素,使得N1钢在较高的300 ℃温度回火时还能保持一定的抗拉强度,N1钢有大量细小的ε-碳化物析出,使得屈服强度增加,屈强比在0.80以上,45CrNiMoVA钢经180 ℃低温回火后屈服强度在1 550 MPa左右,屈强比只有0.72;经相同条件充氢后,N1钢的慢拉伸强度下降幅度较小,其试样断口中也没有观察到沿晶断裂特征,N1钢的氢脆敏感性明显低于45CrNiMoVA钢。 相似文献
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根据低配碳直接还原—低温熔分工艺制备粒铁的技术思想,考察了渣相成分对熔分开始时间及熔分后铁收得率的影响.试验结果表明,随着CaO添加量的增加,球团熔分开始时间先减小后增加.当CaO添加量为2.0%时,熔分开始时间最短.n(C)/n(O)为0.8时,渣相熔点较低,流动性较好,有利于渣铁分离.综合考虑熔分时间、铁收得率及能耗等,实验室条件下的最佳工艺参数为n(C)/n(O) =0.8,CaO添加量为2.0%,反应时间40 min(熔分开始时间30 min+熔分时间10 min).该条件下铁收得率约为85%,铁粒中铁含量约为94%,金属化率达95%以上,可作为优质的电炉炼钢原料. 相似文献
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It has been known for decades that P is one ofthe principal impurities responsible for temperingembrittlement in alloying steels[1] ,and it is general-ly believed that the equilibrium segregation of impu-rities to grain boundaries(GB) is the fundamentalmechanism of inter- granular embrittlement and thatthis is somehow influenced by the alloying elementspresent,such as nickel and chromium,which areknown to play an important role in the process[2 ] .For example,Mulford R A et al[3] have demons… 相似文献
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通过在高钙烟煤的煤灰中添加不同含量的CaO,用于研究高钙烟煤的熔融特性变化情况和不同CaO含量下煤灰的熔融特性温度的变化情况。并且通过FactSage热力学软件对不同成分的合成灰进行模拟计算,用于对试验结果的佐证。研究结果表明,随着CaO添加量(质量分数)的增加,煤灰的熔融特性温度的整体趋势是先降低而后逐渐增加的。通过不同温度下灰中的矿物组成可以看出,添加一定量的CaO后,会使得高钙煤灰形成一种低温共熔体,从而使得灰熔点达到最低值。随着CaO添加量的继续增大,煤灰中钙硅石以及单晶氧化钙等高熔点矿物出现,煤灰熔点开始逐渐增加。并且从FactSage软件计算出的液相线温度结果和相图结果可以看出,其变化的趋势和熔融特性温度变化的趋势一致。 相似文献
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WANG Wei 《Baosteel Technical Research》2015,(2):3-13
There is an increasing trend for producing copper-containing steels,with copper being either a residual element from scraps or an intentional addition,i.e.,in weathering steel.The issue of surface hot shortness occurs during the hot working of steels containing copper,and a significant amount of work has been performed on this topic.This paper provides a review of related studies on this phenomenon.The formation mechanism,as analyzed,is the liquid metal embrittlement caused by the liquid copper penetration into austenite grain boundaries at the metal surface,where the copper originates from the selective oxidation of the steel at high temperature.On the basis of the mechanism,more importance is placed on analyzing the effect on the phenomenon by varying the controlling factors,including the heating process,alloying additions,and deformation conditions.Possible solutions to the problem are finalized,and some further work must be performed in the future. 相似文献