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51.
52.
《International Journal of Hydrogen Energy》2022,47(77):33105-33111
Hydrogen permeation tests are carried out to evaluate the effect of the quenching medium and tempering temperature on the permeation parameters and density of hydrogen traps, of a Cr–Mo–V low-alloy medium-carbon steel. Three types of steel membranes are tested: 1) in the as-quenched condition, 2) tempered at 235 °C and 3) tempered at 530 °C; each one quenched in two different media: oil or brine. From the as-quenched condition, the apparent concentration of hydrogen and hydrogen flux, tend to decrease as the tempering temperature increases. The membranes in the as-quenched condition and tempered at 530 °C, show lower hydrogen diffusivity and higher density of hydrogen traps than membranes tempered at 235 °C. It is concluded that tempering at 235 °C, promotes hydrogen induced cracking, which is contrary to what has been previously determined. The cracking is related to a higher hydrogen diffusivity and lower density of hydrogen traps. 相似文献
53.
15CrMnMoV钢回火脆性研究 总被引:1,自引:0,他引:1
对15CrMnMoV钢空淬和油淬组织于180~660℃不同温度下回火的变化进行了研究,重点研究了高温回火时该钢中特殊碳化物的析出过程及其对回火脆性的影响。 相似文献
54.
淬硬钢回火参数表达式和HTT图 总被引:1,自引:0,他引:1
本文根据淬硬钢回火时温度和时间作用关系式σ=σ0eQT/RT_(t-m)推导出回火时为获得同一机械性能回火温度和回火时间之同关系的三种表达式,即G—B型、二次型及多项式型。其中多项式型是精确的,并和AISI4027钢实际HTT图进行了对比,表明该式有实用价值。 相似文献
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56.
对复合锯片用钢进行了不同温度和保温时间的回火处理,分别测定和观察了覆层与基板的硬度和显微组织。结果表明:Q345钢基板的板条马氏体在回火过程中逐渐粗化,但其基本特征经较高温度回火后仍能保留下来,而覆层45Mn2V钢的针状马氏体退化速度较快,400℃回火后已观察不到针状特征,导致回火后其硬度下降的趋势大于Q345钢基板,因此复合板的回火温度不宜超过400℃。另一方面,由于碳含量较高,45Mn2V钢覆层在回火过程中碳化物的析出较快且析出量较多,故经过8 h回火后仍能保持高的硬度,而Q345钢基板已经发生明显的软化,因此860℃保温5 min油淬,360~390℃保温6 h回火可获得最佳性能。 相似文献
57.
Tobias Glaser Christian Hones Andre Heilemann Petra von Frieling C. Schräer Marc Lörcher 《化学,工程师,技术》2017,89(9):1239-1246
Taste and smell are important quality criteria for chocolate. Beyond this the gloss and texture are relevant. Different process parameters influence the gloss as well as other criteria such as shelf life and fat bloom resistance. In this work a measurement method is introduced and adapted to small chocolate articles. With this, the gloss can be measured reproducible. Then the different process parameters are varied and the gloss of the chocolate is measured. Different methods to improve the gloss are suggested and observed. 相似文献
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59.
Y. Qu X. He X. Zhang H. Fu X. Cheng X. Liu 《Materialwissenschaft und Werkstofftechnik》2020,51(7):930-937
Heat treatment is of great significance to the performance improvement of high speed steel. Via heat treatment, the microstructure of high speed steel can be improved, thus greatly improving the material performance. The effect of tempering temperature on the microstructure of aluminium-bearing high boron high speed steel (AB-HSS) was investigated by optical microscope (OM), scanning electron microscope (SEM) and x-ray diffraction (XRD). The hardness and wear resistance of the alloy at different tempering temperatures were tested by Rockwell hardness tester, micro-hardness tester and wear tester. The experimental results indicate that the tempering microstructure of aluminium-bearing high boron high speed steel consists of α-Fe, M2B and a few of M23(C, B)6. Tempering temperature could greatly affect the wear resistance of materials. With the increase of tempering temperature, the wear resistance of aluminium-bearing high boron high speed steel firstly increase and then decrease. The alloy tempered at 450 °C has the best wear resistance and minimum wear weight loss. This study provides a reference for the formulation of heat treatment process of aluminium-bearing high boron high speed steel. 相似文献
60.
The microstructures and properties of a 0.28C–0.22Ti low-alloy wear-resistant steel at different temperatures from 200 to 600°C was experimentally studied. It is shown that the wear resistance of the steel is not monotone changing with its hardness and strength. With the increase of the tempering temperature, the tensile strength and the hardness of the steels were gradually declined; however, the wear resistance was first decreased and then increased. The TiC particles can be divided into two classes: the small TiC particles (about 0.3–0.4?µm in diameter) and the coarse TiC particles (1–5?µm in diameter). The small TiC particles can improve the yield strength of the steels, and the coarse TiC particles can improve the wear resistance of the tested steels. 相似文献