CN103509994A

CN103509994A - Low carbon steel plate for pressure-bearing equipment and normalizing process thereof

Info

Publication number: CN103509994A
Application number: CN201210205571.XA
Authority: CN
Inventors: 高志国; 程德富; 李培德; 史文义; 康利明; 王海明; 张辉
Original assignee: Baotou Iron and Steel Group Co Ltd
Current assignee: Baotou Iron and Steel Group Co Ltd; Inner Mongolia Baotou Steel Union Co Ltd
Priority date: 2012-06-21
Filing date: 2012-06-21
Publication date: 2014-01-15

Abstract

Belonging to the technical field of steel material heat treatment, the invention relates to a low carbon steel plate for pressure-bearing equipment and a normalizing process thereof. The steel plate comprises the following chemical components (wt%): less than or equal to 0.20% of C, 0.3%-0.5% of Si, 1.0%-1.6% of Mn, less than or equal to 0.020% of P, less than or equal to 0.005% of S, less than or equal to 0.30% of Cu, less than or equal to 0.25% of Cr, less than or equal to 0.25% of Ni, less than or equal to 0.05% of Mo, less than or equal to 0.035% of Nb, less than or equal to 0.03% of Ti, greater than or equal to 0.02% of Al, less than or equal to 0.002% of Ce, and the balance Fe and inevitable impurities. According to a heat treatment technology system, the normalizing temperature is 900-950DEG C, the temperature holding time is 0.2-2h, and the steel plate is discharged from the furnace to undergo air cooling. The steel plate treated by the normalizing heat treatment process has excellent mechanical properties, tensile strength up to 450-600MPa, yield strength of 300-460MPa, elongation of 22-32%, impact energy of over 27J under -20DEG C, and qualified 180-degree cold-bending (d=a). The process has the characteristic of low production cost, and is applicable to industrial production of steel plates with thickness of 20-50mm.

Description

Mild steel plate and normalizing process thereof for a kind of bearing device

Technical field

The invention discloses mild steel plate and normalizing process thereof for a kind of bearing device, belong to ferrous materials heat treatment technics field.

Background technology

Steel Used for Pressure Retaining Components plate is widely used in the industries such as chemical industry, machinery, metallurgy, petrochemical industry, shipbuilding, nuclear power, and kind and specification are various, and environment for use is complicated, and operating temperature range is wider.With regard to nuclear power plant reactor steel heavy plate for pressure vessels, the reactor housing of reactor periphery belongs to Nuclear safety secondary with steel, conventionally uses highquality carbon steel and Hi-Stren steel.At present external generation Ⅲ nuclear power technological project is mainly used P265GH.The steel plate of China's development this type is started late.In recent years, Wuhan Iron & Steel (Group) Corp. produced in nuclear island containment steel liner with WHD265 and WHD585E steel and was applied to domestic nuclear power engineering according to s-generation modified version and generation Ⅲ nuclear power technical requirements.At present, Baosteel, Ji steel, the domestic iron and steel enterprises such as Taiyuan Iron and Steel Co. have possessed the ability of producing used in nuclear power station steel plate, and the product of Some Enterprises has been applied in the Nuclear power projects such as Zhejiang San Men and Haiyang Shandong.

The development of China's steel for nuclear power pressure equipment should mainly design chemical composition, guarantees that steel have good toughness and anti-radiation embrittlement performance, makes rational rolling and thermal treatment process, guarantees steel plate homogeneity of structure and tough index.Yet the trades mark such as P265GH, 20HR be take as main in generation Ⅲ nuclear power station with Steel Used for Pressure Retaining Components plate, in addition less about the steel plate development report of this type of purposes.The invention discloses a kind of low-carbon (LC) Steel Used for Pressure Retaining Components plate, and obtain high-performance bearing device mild steel plate novel material by normalizing thermal treatment.

Summary of the invention

The object of this invention is to provide a kind of bearing device mild steel plate, and obtain quality plate novel material by optimizing thermal treatment process.Realize technical scheme of the present invention as described below, the steel plate that contains following chemical composition is put into process furnace and heat-treat heating, air cooling after insulation for some time.

The chemical composition of steel plate and content (weight percent) are: C≤0.20%, Si0.3%-0.5%, Mn1.0%-1.6%, P≤0.020%, S≤0.005%, Cu≤0.30%, Cr≤0.25%, Ni≤0.25%, Mo≤0.05%, Nb≤0.035%, Ti≤0.03%, Al >=0.02%, Ce≤0.002%, surplus is Fe and inevitable impurity.System of heat treatment process is: normalizing temperature 900-950 ℃, soaking time 0.2-2 hour, the air cooling of then coming out of the stove.The steel plate that normalizing heat treatment technique is processed thus has good mechanical property, and tensile strength reaches 450-600MPa, yield strength 300-460MPa, and unit elongation 22-32%, ballistic work is greater than 27J at-20 ℃, and 180 ° of (d=a) clod washes are qualified.

Accompanying drawing explanation

Fig. 1 is embodiment 1 normalizing state metallographic structure;

Fig. 2 is embodiment 2 normalizing state metallographic structures.

Embodiment

Below in conjunction with embodiment, the present invention is explained in detail.

Embodiment 1:

(weight percent) chemical composition content of steel plate is: C0.084%, Si0.417%, Mn1.28%, P0.0162%, S0.003%, Cu0.208%, Cr0.228%, Ni0.198%, Mo0.046%, Nb0.027%, Ti0.020%, Al0.047%, Ce0.0001%, surplus is Fe and inevitable impurity.Steel plate thickness is 20mm, and its system of heat treatment process is: 900 ℃ of normalizing temperatures, soaking time is after 30 minutes, the air cooling of coming out of the stove.Sampling detects, and its mechanical property detected value is in Table 1.Metallographic structure as shown in Figure 1, be take ferrite and pearlite as main, and mean grain size is 10 grades.

Table 1 mechanical property detected value

Embodiment 2:

(weight percent) chemical composition content of steel plate is: C0.20%, Si0.457%, Mn1.37%, P0.0163%, S0.003%, Cu0.223%, Cr0.196%, Ni0.138%, Mo0.044%, Nb0.025%, Al0.039%, Ce0.0001%, surplus is Fe and inevitable impurity.Steel plate thickness is 20mm, and its system of heat treatment process is: 900 ℃ of normalizing temperatures, soaking time is after 30 minutes, the air cooling of coming out of the stove.Sampling detects, and its mechanical property detected value is in Table 2.Metallographic structure as shown in Figure 2, be take ferrite and pearlite as main, and mean grain size is 10 grades.

Table 2 mechanical property detected value

Claims

1. a bearing device mild steel plate, is characterized in that its chemical composition and content are by weight percentage: C≤0.20%, Si0.3%-0.5%, Mn1.0%-1.6%, P≤0.020%, S≤0.005%, Cu≤0.30%, Cr≤0.25%, Ni≤0.25%, Mo≤0.05%, Nb≤0.035%, Ti≤0.03%, Al >=0.02%, Ce≤0.002%, surplus is Fe and inevitable impurity.

2. a normalizing process for mild steel plate for a kind of bearing device of feature as claimed in claim 1, is characterized in that system of heat treatment process is: normalizing temperature 900-950 ℃, and after soaking time 0.2-2 hour, the air cooling of coming out of the stove.