20MnVB alloy structural steel

1. Introduction

20MnVB alloy structural steel is a kind of low-alloy high-strength structural steel, which is one of the most widely used steels in modern production. It is characterized by good weldability and formability, excellent plasticity and toughness, low hardenability, low temperature impact toughness and other excellent properties. Therefore, it is the first choice material for the manufacture of various structural parts with large stress and complex shape.

2. Chemical Composition

20MnVB alloy structural steel is a low-alloy high-strength structural steel. Its chemical composition is as follows (WT. %):

C: 0.16-0.22; Si: 0.17-0.37; Mn: 1.00-1.60; P≤0.035; S: ≤ 0.035; Mo: ≤ 0.15; V: 0.07-0.12; B: 0.0005-0.003.

3. Features of 20MnVB Alloy Structural Steel

(1) Good weldability and formability: the 20MnVB alloy structural steel has high plasticity during heat treatment, and the hot deformation is large. But there is no hot crack tendency like 16Mn and 17Mn4.

(2) Good low temperature impact toughness: when the temperature is low, the 20MnVB alloy structural steel has good low temperature impact toughness.

(3) Low hardenability: Because of the high content of C, Si and Mn, the 20MnVB alloy structural steel has higher the carbon equivalent than that of low alloy high strength steel with the same strength, so it is not easy to crack in quenching.

4. Application

20MnVB alloy structural steel is widely used in various engineering structures, such as automobile frames, railway vehicles, bridge components, shipping containers, lifting machinery, construction machinery and steel structures. It can also be used to make forgings with pressure vessels, boilers and machinery parts.

5. Heat Treatment

20MnVB alloy structural steel is a low-alloy high-strength structural steel with low hardenability. Therefore, in order to obtain appropriate mechanical properties and structural performance, appropriate heat treatment conditions must be selected.

Normalizing or normalizing and tempering can be adopted to maintain the good plasticity of 20MnVB alloy structural steel. In addition, quenching and tempering treatment can be adopted for parts with higher requirements for mechanical properties and anti-fatigue integral limit δ5%.

6. Development Prospect

With the design thickness of the parts being reduced, the steel grade of 20MnVB alloy structural steel is more and more widely used in various light vehicles and workshapes. As the demand for light and efficient structures increases, 20MnVB structural steels will develop faster and faster and be recognized by more and more fields. In future, the development and application of high-strength structural steel such as 20MnVB alloy structural steel will be the focus of attention.

20MnVB Alloy Structural Steel

20MnVB alloy structural steel belongs to the China pearlitic heat resistant steel (from ordinary carbon structural steel to special purpose steel), which is widely used in the manufacture of welded structures and components. 20MnVB alloy structural steel is made of 20MnVB alloy steel smelting, and then by hot rolling, normalizing, normalizing, tempering and other processing.

20MnVB alloy structural steel due to its high strength, good toughness, plasticity and cutting performance and other characteristics, used in auto frame and wheel, mechanical parts and other parts.

Chemical composition of 20MnVB alloy structural steel:

C 0.17-0.24, Si 0.17-0.37, Mn 1.40-1.80, P ≤ 0.035, S ≤ 0.035, Cr 0.90-1.20, V 0.08-0.15, Ni 0.030, Cu ≤ 0.03.

20MnVB alloy structural steel physical properties:

Tensile strength σb (MPa): ≥850; Yield strength σs (MPa): ≥640; Elongation δ5 (%): ≥7.

Using 20MnVB alloy structural steel, need to pay attention to the following:

1. The flame cutting pieces should be annealed before welding, and the welding process should pay attention to selecting proper welding material and parameters.

2. Tempering temperature should not exceed 540 degree celsius. The tempering temperature should be selected reasonably based on mechanical properties requirements.

3. Hypoeutectoid steel temper brittle at low temperature, should be preheating before tempering to avoid the temper brittleness effect.