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Alloy constructional steels are easily overheated during the forge heat-ing. It is now wellrecognized that at high austenitizing temperatures sulphi-de inclusions can be taken into solution and repreccipitated on austenite grainboundaries during subsequent cooling. This leads to the phenomenon of overhea-ting, which is in company with a drop in impact toughness and an Rock-salt fracture appearance. Overheated steels can be reclaimed by interposingan annealittg operation below the loawer critical Temperaure before... Alloy constructional steels are easily overheated during the forge heat-ing. It is now wellrecognized that at high austenitizing temperatures sulphi-de inclusions can be taken into solution and repreccipitated on austenite grainboundaries during subsequent cooling. This leads to the phenomenon of overhea-ting, which is in company with a drop in impact toughness and an Rock-salt fracture appearance. Overheated steels can be reclaimed by interposingan annealittg operation below the loawer critical Temperaure before the finalhardening and tempering treatment, In this paper the beat treatment by whicht?e distrucution o MnS can be altered, will te described and discussed. Thenthe Rock--salt fracture can be eliminated and the overheated steels obtaintoughness at or above the non--overheated level. 合金结构钢在锻造加热时容易产生过热。现已确认:在高的奥氏体化温度下,硫化物夹杂溶解并在随后的冷却过程中沿奥氏体晶界析出,就导致了过热现象并伴随着冲击韧性的降低和石状断口的出现。在最后的淬火和回火处理之前,插入一道临界点以下的退火工艺,可以矫正过热钢材。本文对于这种能够改变MnS分布的热处理工艺进行了介绍和讨论。通过这种处理,石状断口被抑制,过热钢材的韧性得以恢复并且超过未过热时的水平。 The change of the tensile strength of the C/A1 composite wiras and the content of the aluminum carbide in the interfaces have been studied. The authors note the strength of composite wires was damaged after long period beat-treatment at 495℃ and was damaged remarkably above 540℃, and the content of the aluminum carbide increases with increaasing the temperature and the lime of treatment. 本文研究了经长时间(100个时)高温热处理之后碳-铝复合材料的拉伸强度和碳化铝(Al_4C_3)量变化的情况。观察到碳—铝复合材料在495℃长时间热处理其强度降低,在540℃长时间热处理其强度明显下降。碳化铝的数量和强度值在某一温度对在某一时间之后变化趋于平缓。 Depositi on and gas sensing characteristic of SnO_2 thin film prepared by rf sputtering have been investigated. In order to improve gas sensing property, a Pd doped SnO_2 film was used. Pd film of a few tens (?) thick was sputtered on the deposited SnO_2 film. The Pd doped layer was formed after beat treatment.AES and ESCA of the SnO_2 film showed that the film was composed of SnO_x, without any tin element. Composition distribution both on surface, and in depth of SnO_2 film were uniform.Gas sensing characteristic... Depositi on and gas sensing characteristic of SnO_2 thin film prepared by rf sputtering have been investigated. In order to improve gas sensing property, a Pd doped SnO_2 film was used. Pd film of a few tens (?) thick was sputtered on the deposited SnO_2 film. The Pd doped layer was formed after beat treatment.AES and ESCA of the SnO_2 film showed that the film was composed of SnO_x, without any tin element. Composition distribution both on surface, and in depth of SnO_2 film were uniform.Gas sensing characteristic of SnO_2 film strongly depended upon substrate temperature. The SnO_2 film was sensitive for CH_4、CO、H_2、H_2S and NO_2 gases at above 200℃, while the Pd/SnO_2 film was shown with good sensing response at 150℃ and improved selectivity. 应用射频溅射法制备SnO_2膜。对SnO_2膜进行了AES、ESCA理化学分析,结果表明:SnO_2膜的成分完全由SnO_2所组成,膜中并没有分离的Sn的成分。同时也对SnO_2膜进行了气敏特性测试分析,结果表明:SnO_2和Pd/SnO_2膜对CH_4、CO、H_2、NO_2、H_2S等气体均有明显的敏感特性,当SnO_2膜表面掺入几十(?)P_d后,对上述气体的敏感性有所增加,工作温度可降低到150℃左右,选择性也有不同程度的改善。
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