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1 前言 容器板16MnR主要用于制造二、三类压力容器,对材质的内在质量包括理化性能和超声波探伤要求较高,我公司生产的容器板近两年由于探伤合格率偏低,影响产品质量。本文通过对探伤缺陷进行系列研究,确定了缺陷产生原因,并提出了相应的措施。2 缺陷分析 1996年l～6月份16MnR探伤合格率比较低。影响探伤级别的主要是缺陷的指示长度和单个缺陷指示面积超过标准规定。而造成探伤不合主要缺陷是密集型缺陷,且密集型缺陷往往造成整炉不合,1996年l～6月份因密集区缺陷造成探伤合格率低。所谓密集区缺陷是指在50 X 50mm的检测面上,发现在同一深度范围内有5个或5个以上的缺陷反射信号,其反射波幅均大于某一特定当量缺陷基准反射波幅“”。密集区缺陷分布规律是以点状缺陷密集分布于整个板面,点状缺陷直径为smm左右,缺陷没有指示长度,探头移动伤波消失。造成密集型缺陷的原因目前有几种论点:其一是夹杂学说,其二是白点学说。按标准规定钢材中不允许存在白点缺陷,有白点等严重影响产品质量的缺陷应判为废品。 本文通过试验研究结果否定了以上两种论点,认为密集性缺陷为氢在夹杂物密集处聚集形成气体富集区与密集的夹杂物共同引起的。因而产生密集型缺陷的主要原因是气体,其次是密集的硫化锰等夹杂物。而造成?
1 Introduction Container plate 16MnR is mainly used to manufacture two or three types of pressure vessels, the inherent quality of the material, including physical and chemical properties and ultrasonic testing requirements are high, the container plate produced by our company in recent two years because of low pass rate, affecting product quality . In this paper, through a series of research on flaw detection flaws, the causes of flaws are determined and the corresponding measures are put forward. 2 Defect Analysis 1996 l ~ June 16MnR testing pass rate is relatively low. The main impact of the level of inspection is the length of the defect indication and a single defect indication area exceeds the standard requirements. The main defects caused by testing defects are intensive defects, and intensive defects often lead to the furnace altogether, 1996 l ~ 6 months due to defects caused by the detection of low qualified pass. The so-called dense area defect refers to the 50 X 50mm detection surface, found in the same depth range of 5 or more defects reflected signal, the reflection amplitude is greater than a specific equivalent defect reference reflection amplitude “”. Defects in dense area distribution of defects are densely distributed in the entire board surface defects, punctate defect diameter of about smm, defects without indication length, the probe moving wounded disappears. Causes of intensive defects There are several arguments at present: one is inclusion theory, and the second is white point theory. According to the standard provisions of steel does not allow the existence of white point defects, white spots and other serious impact on product quality defects should be sentenced to waste. In this paper, the above two arguments are negated by the results of the experimental study. It is considered that the dense defect is caused by the accumulation of hydrogen and dense inclusions in the dense areas where inclusions are formed. The main cause of the dense defects is therefore gas, followed by dense inclusions such as manganese sulfide. And cause?