Product Introduction

Ductile iron Overview

Ductile castings effectively improve the mechanical properties of cast iron, especially improve the plasticity and toughness, so as to obtain higher strength than carbon steel. Ductile iron is a kind of high strength cast iron material developed in the 1950s, its comprehensive performance is close to steel, it is based on its excellent performance, has been successfully used to cast some complex forces, strength, toughness, wear resistance requirements of high parts. Ductile iron has rapidly developed into a cast iron material second only to gray iron and widely used. The so-called "iron instead of steel" mainly refers to ductile iron.

Ductile iron composition

Pig iron is an iron-carbon alloy with a carbon content of more than 2%, and the carbon content of industrial pig iron is generally 2.5%--4%, and contains C, SI, Mn, S, P and other elements, which is the product of smelting iron ore by blast furnace. According to the different forms of carbon in pig iron, it can be divided into steelmaking pig iron, cast pig iron and ductile iron.

A cast iron whose graphite is spherical in shape. The cutting effect of spherical graphite on metal matrix is smaller than that of flake graphite, so that the strength of cast iron can reach 70 ~ 90% of the strength of the matrix, the tensile strength can reach 120kgf/mm2, and it has good toughness. In addition to iron, the chemical composition of ductile iron is usually: carbon content 3.6 ~ 3.8%, silicon content 2.0 ~ 3.0%, the total amount of manganese, phosphorus, sulfur does not exceed 1.5% and an appropriate amount of rare earth, magnesium and other nodulators.

Ductile iron castings have been used in almost all major industrial sectors, which require high strength, plasticity, toughness, wear resistance, resistance to severe thermal and mechanical shock, resistance to high or low temperatures, corrosion resistance and dimensional stability. In order to meet these changes in the conditions of use, ductile iron is available in many grades, providing a wide range of mechanical properties and mechanical properties.

Most nodular cast iron castings, as specified by the International Organization for Standardization 1501083, are mainly produced in a non-alloying state. Obviously, this range includes high strength grades with tensile strength greater than 800 newtons/mm and elongation of 2%. At the other extreme are high plastic grades with elongation greater than 17% and correspondingly low strength (* as low as 370 Newton/mm scoop). Strength and elongation are not the primary factors in the designer's choice of materials, and other critical properties include yield strength, modulus of elasticity, wear resistance and fatigue strength, hardness and impact properties. In addition, corrosion resistance and oxidation resistance as well as electromagnetic properties may be critical for designers. In order to meet these special uses, a group of austenitic ductile iron has been developed, which is usually called austenitic ductile iron. These austenitic nodules are mainly alloyed with zinc, chromium and manganese and are included in international standards.

Ductile iron manufacturing steps

(1) Strict requirements for chemical composition, the carbon silicon content of the original iron liquid is higher than that of gray cast iron, and the content of manganese, phosphorus and sulfur in ductile cast iron is reduced

(2) The temperature of liquid iron is higher than that of gray cast iron, which compensates for spheroidization and the loss of liquid iron temperature during inoculation

(3) spheroidizing treatment, that is, adding spheroidizing agent to the iron liquid

(4) Carry out incubation treatment

(5) The flow of ductile iron is poor, the shrinkage is large, so the need for higher pouring temperature and larger pouring system size, the application of riser, cold iron, the use of sequential solidification principle

(6) Heat treatment

Zhongwei Precision has the following services

Detection Systems

Copper Silica Sol Investment Casting

We are the manufacturer of "SG600 Slash/3 Ductile Iron Parts", if you need more information please contact us!