The hot rolling technoledge of JIS G 3125 SPA-H weatherproof steel plate for container

The container manufacturing industry has strict requirements for atmospheric corrosion resistance of steel materials, and its demand for JIS G 3125 SPA-H weatherproof steel plate is increasing at a relatively high speed in recent years. The SPA-H steel plates are mainly produced by hot rolling technoledge.

The JIS G 3125 SPA-H weatherproof steel plate billet is heated and pumped to 1500 mm hot strip mill. The Cu content of SPA-H steel is relatively high, and copper brittleness is easy to occur during heating. When heating, the cracks on the surface of SPA-H steel billet will cause cracking. Therefore, the heating adheres to the principle of "high temperature fast burning", which ensures that the billet is heated in the reduction or neutral atmosphere, speeds up the heating speed, increases the temperature of the heating section, prevents excessive oxidation, reduces the concentration of Cu on the grain boundary and the surface of the cast billet, and avoids the edge crack during the rolling of JIS G 3125 SPA-H weatherproof steel plate, and reduces the heat mean temperature properly. The billet temperature is 1160~1210 and the heating time is no less than 80 min.

The SPA-H steel material is hard, and the rolling specifications of JIS G 3125 SPA-H weatherproof steel plates are usually thin. The rolling force and rolling current of the finishing mill are relatively large during the rolling process, which are prone to accidents. Therefore, the thickness of intermediate billets should be reduced appropriately. According to the specifications of finished products, the thickness of intermediate billets is generally selected at 26~29 mm. After the strip rolling mill is finished, the water cooling is carried out in a dense manner, the front stage is accelerated, and the rear section controls the coiling temperature. The coiling temperature is 620 + 15 DEC.