HU Zheng-fei
,
WANG Qi-jiang
,
ZHANG Bin
钢铁研究学报(英文版)
Standardarized creep and rupture strength tests were conducted for commercial T91 martensitic heat-resistant steel at 650 ℃ and corresponding microstructure was characterized by BSED, TEM and EDS. The martensitic microstructure degenerated seriously during creep exposure, including martensitic substructure recovering, carbides coarsening, dissolving and precipitating. EDS analysis shows that the M23C6 carbides in different morphologies have dissimilar compositions. The rod/sheet like M23C6 particles within the matrix contain more additions, which might precipitate in situ while fine MX particles were re-solving. The high content of silicon in these rod/sheet like M23C6 carbides is probably related to self diffusion coefficient increasing for the exposed condition at 650 ℃ close to Curie temperature Tc. For those reasons, martensite substructure becomes unstable, and microstructure evolution is accelerated and leads to creep strength deteriorating severely.
关键词:
T91 steel
,
creep strength
,
microstructure
,
carbide
,
coarsening
,
self-diffusion
田俊，刘岩，成国光
钢铁
对H13钢试样进行了退火试验，对退火前后试样进行了硬度测试及扫描电镜和能谱分析。分析了H13钢热轧材硬度不均匀性的形成原因。结果表明，低倍“黑斑”区域硬度平均值为91.43HRB，比正常区域高7.53%；“黑斑”区域主要由“白斑”和“黑色质点”组成，“白斑”化学成分主要是铁，“黑色质点”主要成分为合金碳化物；H13钢试样经退火后，原“黑斑”区域硬度明显降低，从190.2HB下降到168.26HB，退火后“黑色质点”尺寸变小，其碳质量分数大幅度降低，从80%下降到15%；H13钢热轧材硬度不均匀主要是由于钢液凝固过程中成分不均匀所致。
关键词:
H13钢
,
freckle
,
carbide
,
hardness
,
annealing
王康
,
，杨卯生，樊刚，俞峰，鲍俭
,
，闫文凯
钢铁
对16Cr14Co12Mo5耐热耐蚀轴承钢在1050℃高温淬火后，在490～540℃两次回火后的组织性能以及强韧化机制进行研究。结果表明：随着回火温度的升高，抗拉强度Rm逐渐增加，最大时超过了1900MPa，屈服强度Rp0.2在500℃回火后达到1400MPa，随后逐渐减小；断面收缩率和伸长率略有减小，而硬度略有增长。材料强韧化主要源于高位错板条马氏体以及其中残余奥氏体薄膜和沉淀析出的碳化物和金属间化合物。采取适宜淬回火工艺制度所导致弥散析出的碳化物和金属间化合物是试样的强度和韧性达到最佳配合的关键。
关键词:
轴承钢
,
precipitation
,
carbide
,
intermetallic compound
