所属分类：常见问题 发布时间：2021-01-28 13:50:28 来源：http://www.lcnmb500.com 浏览量：
The equilibrium solubility of hydrogen in pure iron is about 0.3 ml / 100 g at 400 ℃ and about 0.0005 ml / 100 g at room temperature under the pressure of 1 atmosphere. However, the hydrogen content in the welding zone of hardox600 wear-resistant plate steel is as high as several ml ~ tens of ml / 100g at room temperature. Therefore, the excess hydrogen exists as supersaturated atomic hydrogen and molecular hydrogen accumulated in the intragranular defects and grain boundaries.
It is found that the former (atomic hydrogen) diffuses into the steel and escapes from the surface with time at room temperature, while most of the latter remains intact. However, if it is heated to a high temperature above 2000c, it will become atomic hydrogen and escape from the surface.
In order to quantitatively measure the total hydrogen content in hardox600 wear-resistant steel plate in a short time, it can be heated to 650-800 ° C in vacuum or conveying gas and extracted.
The content of diffusible hydrogen in the coated arc welding rod for high strength steel is lower. In addition, this regulation is applicable to the electrode with a diameter of 4 mm. However, there is almost no difference in the diffusible hydrogen content of the electrode with the same coating with different diameters.
At present, the diffusion hydrogen content of actual electrode is about half of the specified value when it is dried at the specified temperature (350-400 °). However, in the case of moisture absorption, the hydrogen content increases significantly.
The higher the diffusible hydrogen content of the coated arc electrode and the indoor humidity (correctly speaking, the partial pressure of water vapor in the atmosphere) during welding, the more it will be. Therefore, some electrode manufacturers show the measured value in the product samples under the conditions of standard atmosphere (20 ° C, humidity 65%, partial pressure 10.52 mmHg).
Therefore, it must be noted that when hardox600 wear-resistant steel plate is welded under high humidity, the diffusible hydrogen content is 2 ~ 3ml / 100g higher than that specified in the product sample.