Why are there bubbles on the surface of ASTM A588 weathering steel

1. The temperature of the extrusion cylinder and the extruded ingot is too high;

2. The temperature and size of the steel ingot exceed the allowable negative deviation range of ASTM A588 weathering steel.

3. The ingot is too long, the filling is too fast, and the temperature of the ingot is uneven, resulting in non-drum filling, incomplete exhaust of the cylinder, or improper operation and poor exhaust.

4. The die hole design of ASTM A588 weathering steel is improper, or the amount of residual data is too much during cutting, and the residual data in the shunt holes and shunt holes are partially removed. During the extrusion process, the gas in the air gap flows into the surface. After the ASTM A588 weathering steel is hot rolled or forged, it does not undergo special heat treatment, but is shipped directly after cooling. This state is called hot rolling or hot forging.

Under normal circumstances, the end temperature of hot rolling of ASTM A588 weathering steel is 800~900℃, and then it is naturally cooled in the air, so the hot rolling state is normalized. The difference is that the final temperature of hot rolling is higher or lower than the normalizing temperature.

Unlike normalizing, the heating temperature is not strictly controlled, so the structure and properties of ASTM A588 weathering steel fluctuate more than during normalizing.

We adopt a controlled rolling process. In the finishing rolling process, through strict temperature control and forced cooling measures, the grains are refined, thereby improving the comprehensive mechanical properties of ASTM A588 weathering steel.