Q245R 20g 16Mng 15CrMoVg Boiler Steel Plate

Boiler steel plates mainly refer to the materials used to manufacture superheaters, main steam pipes and heating surfaces of boiler fire chambers. The performance requirements for boiler steel are mainly good welding performance, certain high temperature strength and alkali corrosion resistance, oxidation resistance and so on. Commonly used boiler steels are low carbon killed steel smelted by open hearth or low carbon steel smelted by electric furnace, and the carbon content Wc is in the range of 0.16%-0.26%. When manufacturing high-pressure boilers, pearlitic heat-resistant steel or austenitic heat-resistant steel is used. In recent years, ordinary low-alloy steels have also been used to build boilers, such as 12 manganese, 15 manganese vanadium, 18 manganese molybdenum niobium, etc.

(1) The main steel grades of boiler plates are: 20g, 16Mng, 15CrMoVg, 19Mng, 22Mng

(2) The main steel grades of plates for pressure vessels are: 20R, 16MnR, 15MnNbR, 15MnVNR

(3) Executive standards: GB713-1997, GB6654-1996

As boiler steel plate is an important product with strict safety and reliability requirements and high manufacturing technology difficulty, the material must have the following main characteristics:

1.The material has high yield strength performance in a certain temperature range (medium and normal temperature and high temperature);

2.The material has sufficient toughness, and no brittle failure accident will occur during manufacture or use;

3.The material has a small strain aging sensitivity, especially in the corresponding working temperature region, a certain value of aging impact energy must be guaranteed;

4.The material has low notch sensitivity, which can prevent steel cracks in welding, opening, and local stress concentration areas;

5.The material has good welding performance;

6.The material has a good microstructure, and white spots and cracks are not allowed

According to GB/T 13304 standard, spring steel is divided into non-alloy spring steel (carbon spring steel) and alloy spring steel according to its chemical composition.

Common Grades:

1. 65, 70, 85 steel grades

High strength, hardness and yield ratio can be obtained, but the hardenability is small, the heat resistance is not good, and the ability to withstand dynamic and fatigue loads is low. It is widely used, but it is mostly used for small springs with low working temperature or less Important larger spring. Such as springs for automobiles, tractors, railway vehicles and general machinery.

The composition of 65Mn is simple, and its hardenability, comprehensive mechanical properties, decarburization and other process properties are better than carbon steel, but it is more sensitive to overheating, has temper brittleness, and is prone to cracks during quenching. The price is low and the amount is large. It can manufacture various small-section flat springs, round springs, springs, etc., as well as valve springs, spring rings, shock absorbers, clutch reeds, brake springs, etc.

2. 55Si2Mn, 60Si2Mn, 60Si2MnA

High silicon content (Wsi) (up to 2.00% upper limit).

High strength and good elasticity. Good anti-tempering stability. Easy to decarburize and graphitize. Hardenability is not high.

The main spring steel type, has a wide range of uses. Manufacture of various springs, such as leaf springs, coil springs for automobiles, locomotives, and tractors, cylinder safety valve springs and some important springs that work under high stress, and springs that are severely worn.

55Si2MnB Due to the boron content, its hardenability is obviously improved. Front and rear suspension springs and auxiliary springs of light and medium-sized automobiles.

55Si2MnB The steel grade developed by China, its hardenability, comprehensive mechanical properties and fatigue properties are better than 60Si2Mn steel. It is mainly used for the manufacture of leaf springs for medium and small cars. .

3. 60Si2CrA 60Si2CrVA

High strength spring steel. High hardenability, good heat treatment process performance. Due to the high strength, the important large springs with large load should be handled in time to eliminate internal stress after coiling the spring. 60Si2CrA can be used to make steam turbine seal springs, regulating springs, condenser support springs, high-pressure water pump disc springs, etc. 60Si2CrVA steel also makes extremely important springs, such as springs for conventional weapons and springs, and springs for breakers.

4. 55CrMnA

The outstanding advantages of 60CrMnA are good hardenability, in addition to hot working properties, comprehensive mechanical properties, anti-decarburization properties, and various important springs with large cross-sections, such as large leaf springs and coil springs for automobiles and locomotives.

5. 60CrMnMoA

It has the highest hardenability among all existing spring steels. Good mechanical properties, anti-tempering stability, etc. Super-large springs used in large-scale civil construction, heavy-duty vehicles, machinery, etc. The thickness of the steel plate can reach more than 35mm, and the diameter of the round steel can exceed 60mm.

6. 50CrVA

A small amount of vanadium improves elasticity, strength, yield ratio and elastic reduction resistance, refines grains, and reduces the tendency of decarburization. The carbon content is small, and the plasticity and toughness are better than other spring steels. High hardenability and good fatigue performance All kinds of important coil springs are especially suitable for springs with high working stress amplitude and strict fatigue performance requirements, such as valve springs, fuel injector springs, cylinder expansion rings, safety valve springs, etc.

7. 60CrMnBA

The hardenability is higher than that of 60CrMnA, and other various properties are similar. Larger size leaf springs, coil springs, torsion springs, etc.

8. 30W4Cr2VA

High strength heat resistant spring steel. Hardenability is good. High temperature relaxation resistance and thermal processing performance are also very good. Heat-resistant springs with working temperature below 500~C, such as steam turbine main steam valve springs, steam seal spring sheets, boiler safety valve springs, 400t boiler disc valve springs, etc.

Mechanical Properties of Typical Chinese Spring Steel Grades