Low crack sensitivity steel plate with yield strength 500MPa and manufacturing method thereof

Abstract

The invention discloses a crack sensitivity steel plate with the yield strength of 500MPa, which is characterized by comprising the following chemical elements in terms of weight percentage: 0.010 to 0.09 percent of C, 0.10 to 0.65 percent of Si, 1.10 to 2.00 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.006 percent of S, 0.020 to 0.090 percent of Nb, 0.02 to 0.06 percent of Al, 0.004 to 0.030 percent of Ti, 0.0005 to 0.0025 percent of B and the balance of Fe and inevitable impurities. The manufacturing method comprises the following steps: smelting and casting the raw materials into casting blank or steel ingot; 2) heating; 3) rolling; and 4) entering a cooling accelerator, cooling till the temperature of 450 to 560 DEG C, and air cooling after water drainage. The crack sensitivity steel plate has little sensitivity of welded crack, and the welding performance is good when the yield strength is more than 500MPa.

Description

A low crack sensitivity steel plate with a yield strength of 500MPa and its manufacturing method technical field The invention relates to the field of iron and steel metallurgy, in particular to a steel plate with a yield strength of 500 MPa and low crack sensitivity. Background technique In order to facilitate welding and simplify the welding process, for high-strength steel used in mechanical structures and engineering construction, the welding crack sensitivity index Pcm of the steel is required to be as low as possible, so as to achieve the purpose of no preheating before welding. This kind of steel is called High-strength steel with low welding crack sensitivity, also known as CF steel. It is a kind of low-alloy high-strength steel with excellent welding performance and low-temperature toughness. Its advantage is that it does not cause cracks without preheating or slightly preheating before welding. It mainly solves the welding construction problem of large steel stru...

AI Technical Summary

Problems solved by technology

Since Cr, Cu, Mo, and Ni are all precious alloying elements, especially Mo and Ni are more expensive, so from the analysis of the types of alloying elements added, the smelting costs of these two types of steel are relatively high, and the steel plates are required to be smelted separately. Quenching + tempering and off-line tempering treatment, complex manufacturing process

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