Method for producing 65Mn hot rolled steel plate

Abstract

The invention discloses a method for producing a 65Mn hot rolled steel plate, which comprises the steps of smelting, refining, thin slab casting, soaking, high pressure water descaling, hot continuous rolling, cooling and reeling based on the process of thin slab casting and rolling. The molten steel superheat temperature is T superheat (30 DEG C <T superheat < / = 45 DEG C), the charging temperature of casting blanks is T charging (900 DEG C < / = T charging < / = 1050 DEG C), the final rolling temperature is T final (850 DEG C < / = T final < / = 950 DEG C), the reeling temperature is T reeling ( 550 DEG C < / = T reeling < / = 650 DEG C), the liquid core pressure of casting blanks is L pressure (2 < / = L pressure < / = 20mm), and the depth of a single-surface decarburized layer is 0.3 to 0.9 percent of the depth of the steel plate. The chemical constitutes of molten steel after being alloyed in a refining process comprise 0.62-0.70 wt.% of C, 0.17-0.37 wt.% of Si, 0.90-1.20 wt.% of Mn, less than or equal to 0.035 wt.% of P, less than or equal to 0.035 wt.% of S, less than or equal to 0.25 wt.% of Cr, less than or equal to 0.25 wt.% of Ni and the balance of Fe and inevitable impurities. The 65Mn hot rolled steel plate produced in the method has the characteristics of uniform structure property, high thermal stability and high strength, and the quality of the 65Mn hot-rolled steel plate is obviously improved.

Description

technical field [0001] The invention relates to the technical field of spring steel production, in particular to a method for producing 65Mn hot-rolled steel plates. Background technique [0002] 65Mn steel has the advantages of high hardness, good hardenability, less decarburization tendency, low price, good machinability, etc., but it is overheating sensitive, prone to quenching cracks, and has temper brittleness. 65Mn steel is widely used. It is mainly produced into steel wire and steel strip, which is used to manufacture various flat and round springs, leaf springs and spring sheets with less cross-section. 65Mn steel is widely used in the automobile industry, electronics industry, trains and other transportation vehicles. It can also be used to make circular saw blades for high-speed cutting of various types of steel, steel pipes and steel bars. [0003] Thin slab continuous casting and rolling is a new technology for producing hot-rolled thin plates. It organically in...

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Problems solved by technology

[0002] 65Mn steel has the advantages of high hardness, good hardenability, less decarburization tendency, low price, good machinability, etc., but it is overheating sensitive, prone to quenching cracks, and temper brittle

[0004] The following main problems still exist in the existing technology of 65Mn hot-rolled steel plate development and production: due to the high carbon content of 65Mn, complex alloy composition, low casting speed of the thick slab continuous caster, and slow solidification of molten steel, it is easy to cause segregation and loosening of the cast slab composition, resulting in The structure of the final product is uneven; the casting slab is heated by a walking heating furnace, the heating time is long and the temperature is high, and the surface of the slab is seriously decarburized, which directly affects the surface hardness, wear resistance and thermal stability of the product; the solidification temperature of 65Mn is low , poor thermal strength, high crack sensitivity, prone to surface cracks, directly affecting product quality; at the same time, the liquidus temperature of the steel is low, and the pouring temperature and pouring speed are low; Breakout

In addition, there are problems of fluctuations in the hardness of the steel plate and the depth of the decarburization layer after quenching treatment

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