How to judge the quality of steel castings
Steel castings are widely used in hardware and the whole machinery industry. Therefore, it is very necessary for purchasing and using enterprises to select high-quality steel castings and avoid inferior steel castings. So, how to judge the quality of steel castings?
The quality of steel castings can be judged from two aspects: the appearance of products and the internal texture. In terms of product appearance, we should pay attention to whether the surface of steel castings is cracked, whether the surface is smooth, and whether the size meets the standard; For the texture of steel castings, the grain size, whether there are sand holes and pores inside.
First of all, in appearance:
Generally speaking, inferior steel castings have the following surface defects:
1. The surface of inferior steel castings is rough and uneven. A layer of metal oxide is adhered on the surface;
2. The coating of steel castings cracks, resulting in coating scabs or grooves;
3. Collapse of steel castings and wrinkling on the surface;
4. The surface is sticky, and the surface adhesion of steel castings is high, resulting in the appearance of different color from the base of steel castings.
When purchasing steel castings, the purchaser can first touch the steel castings with his hand. The ones with smooth surface, no crack and standard size are better.
Secondly, internal texture:
In order to truly judge the quality of steel castings, it is necessary to further check whether the internal texture of steel castings is uniform. Two methods can be used: on the one hand, the method of knocking is used. If the sound is clear, the product is of high quality; On the other hand, magnetic particle test or infrasound inspection can also be used to ensure that there are no pores, sand holes and other defects inside the product.