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前言 随着内燃机向高速、重载、小体积方面发展,对排气阀的高温和耐蚀性及持久性提出了更高的要求,国外先进的国家如美、日、苏、法、德和国际标准均推荐和广泛应用奥氏体耐热钢、相当我国钢号的5 Cr21Mn9Ni4N钢(简称21—4N)与马氏体钢(国内多数生产厂家用4 Crg9Si2或4Cr10Si2Mo钢)对焊作排气阀,近几年来我国内燃机的排气阀也越来越多的应用此材料和工艺,并在工艺、性能上作了大量的研究: 但对于焊缝质量的检查及要求均无见到详细规定。现查到的日本富士气阀公司有关资料,其中仅规定:(1)焊接面积≥80％;( 2)剪切力要求: φ8mm在1680公斤力以上( 33.42kgf/mm~2—作者注,下同);φ10mm的在2400公斤力以上(30.56kgf/mm~2);φ12mm的在2800公斤力以上(24.76Kgf/mm~2)国内却没有统一规定的标准,只是在行业生产中推荐用φ9.5mm的试样,抗拉断力大于5000公斤力(σ_b>70.54kgf/mm~2);对焊缝进行超声波探伤,用φ14或φ20mm的直探头,在2.5兆赫的超声波强度下的纵波反射法;用排气阀材料及制造工艺仿造人造缺陷槽深分别为1mm、0.5mm、0.25mm,槽宽均为1mm,调节反射波高为50mm;深为0.5mm和0.25mm的调节波高为30mm作为工件检测时的参照
Preface With the development of high speed, heavy load and small volume of internal combustion engine, the high temperature and corrosion resistance and durability of the exhaust valve are put forward higher requirements. Advanced countries such as the United States, Japan, the Soviet Union, France, Germany and International standards are recommended and widely used austenitic heat-resistant steel, equivalent to China’s steel No. 5 Cr21Mn9Ni4N steel (referred to as 21-4N) and martensitic steel (most domestic manufacturers with 4 Crg9Si2 or 4Cr10Si2Mo steel) for welding exhaust Valve, in recent years, China’s internal combustion engine exhaust valve is also more and more applications of this material and process, and in the process, performance, made a lot of research but the quality of the weld inspection and requirements are not met detailed provisions . Now found in Japan Fujitsu valve company information, which only provides: (1) welding area ≥ 80%; (2) shear force requirements: φ8mm at 1680 kilograms of force or more (33.42kgf / mm ~ The same below); φ10mm in more than 2400 kg (30.56kgf / mm ~ 2); φ12mm in more than 2800 kg (24.76Kgf / mm ~ 2) there is no uniform standard, but recommended in the industry φ9.5mm sample, the tensile breaking force of more than 5000 kg force (σ_b> 70.54kgf / mm ~ 2); weld ultrasonic testing, with φ14 or φ20mm straight probe at 2.5 MHz ultrasonic intensity of the longitudinal wave Reflection method; exhaust valve material and manufacturing process imitation artificial defects slot depth of 1mm, 0.5mm, 0.25mm, slot width are 1mm, adjust the reflected wave height of 50mm; depth of 0.5mm and 0.25mm adjustment wave height of 30mm As the workpiece inspection reference