High-strength low-stress cast iron material and preparation process thereof

Abstract

The invention relates to a high-strength low-stress cast iron material and a preparation process thereof. The high-strength low-stress cast iron material is characterized by comprising the following chemical ingredients: 3 to 3.3 percent of C, 1.8 to 2.2 percent of Si, 0.8 to 1.0 percent of Mn, 0.1 to 0.25 percent of Cr, less than 0.12 percent of P, less than 0.1 percent of S and the balance iron. The preparation process of the cast iron material comprises the following steps that: (1) a 10-ton cupola furnace is adopted for smelting, the air quantity is controlled to be 150 to 160 m<3> / min, the air pressure is controlled to be 15 to 16 KPa, the bottom coke height is ensured to be controlled between 2300mm and 2400mm, and the carbon containing quantity is 3 to 3.3 percent; (2) the tapping temperature is controlled to be 1420 DEG C+ / -10 DEG C; (3) the inoculation quantity is controlled to be 0.5 percent, and the chilling width after the inoculation is 0 to 2mm; and (4) the casting temperature is controlled to be in a range being 1360 DEG C to 1380 DEG C. The performance such as the strength, the hardness, the metallographic structure, the internal stress and the like of castings is obviously superior to that of the national standard specified requirement; the cracks and the deformation of the casting rib plates are eliminated, the heat treatment of the castings is not needed, the quality and the production efficiency of products are improved, and the production cost is saved.

Description

technical field [0001] The invention relates to a high-strength and low-stress cast iron material and a preparation process, belonging to the field of material processing. Background technique [0002] The traditional production of high grade (HT300) gray iron castings adopts the principle of low carbon, low silicon and low carbon equivalent to achieve high strength castings. The chemical composition requirements are as follows: C: 2.8—3.1 Si: 1.3—1.7 Mn1.0—1.2 P <0.12 S<0.12, thus, the strength and hardness of the casting meet the requirements, but the internal stress of the casting is greatly increased, cracks are easy to appear, and the corners of the casting have high hardness and are not easy to cut. Moreover, the casting stress is large, and the casting is easy to deform; in order to reduce the internal stress of the casting, heat treatment must be carried out to eliminate it, so as to meet the requirements of use. In this way, in the production process, the pro...

AI Technical Summary

Problems solved by technology

[0002]The traditional production of high grade (HT300) gray iron castings adopts the principle of low carbon, low silicon and low carbon equivalent to achieve high strength castings. The chemical composition requirements are as follows: C : 2.8—3.1 Si : 1.3—1.7 Mn1.0—1.2 P<0.12 S<0.12, thus, the strength and hardness of the casting meet the requirements, but the internal stress of the casting is greatly increased, and cracks are prone to appear, and the corner hardness of the casting is high, so it is not easy to cut processing

Moreover, the casting stress is large, and the casting is easy to deform; in order to reduce the internal stress of the casting, heat treatment must be carried out to eliminate it, so that the meeting requirements can be used.

In this way, in the production process, the production cycle is longer and the cost is higher