Super Strength Of 65Mn Spring Steel

Super strength of 65Mn spring steel

65Mn spring steel is a high-strength steel that has been widely used in various industries due to its exceptional mechanical properties. This steel is known for its high yield strength, excellent toughness, and impressive fatigue resistance, making it ideal for heavy-duty applications.

One of the main advantages of 65Mn spring steel is its remarkable strength. With a maximum tensile strength of 2450 MPa, this steel can withstand significant loads without experiencing plastic deformation or failure. This makes it ideal for applications that require high strength, such as automotive components, construction materials, and aerospace parts.

Another positive aspect of 65Mn spring steel is its durability and resistance to wear and tear. This steel can withstand extreme temperatures, harsh chemicals, and corrosive environments, making it an excellent choice for applications in the oil and gas industry, marine structures, and mining equipment.

Moreover, 65Mn spring steel has good machinability, which means that it can be easily shaped and formed into different shapes and sizes. This makes it a versatile material that can be used for a wide range of applications in different industries.

Basic information

Chinese name:65Mn spring steel

Executive standard:GB/T 1222-2007

Yield strength:520~690(MPa)

Rolled bar:Φ 16 ~ 160 mm

Chemical composition

Carbon C :0.62~0.70

Silicon Si:0.17~0.37

Manganese Mn:0.90~1.20

Sulfur S :≤0.035

P :≤0.035

Chromium Cr:≤0.25

Nickel Ni:≤0.30

Copper Cu:≤0.25

Cold drawing annealing

Traditional cyclic spheroidizing annealing process, annealing temperature 750℃, hold for 2h, furnace cooling to temperature (680±10)℃, hold for 3h, and then furnace cooling to 550℃, air cooling. Low production efficiency, oxidation and decarburization rate of 22%-40%, surface hardness and elasticity can not meet the requirements. New process of incomplete annealing, annealing temperature (740±10)℃, heat preservation for 4h, furnace cooling to 550℃, air cooling. Tensile strength 600-620Mpa, elongation of 53.5%-40%, hardness 209-214HBW metallographic structure of spheroidized pearlite + a small amount of point pearlite, shorten the production cycle, save energy.

Traditional annealing process, annealing temperature 730℃, holding 13h, and then cooling to 650℃, air cooling. New annealing process: annealing temperature (860±10)℃, insulation 45-60min, furnace cooling to (750±10)℃, insulation 3-3.5h, after the furnace cooling to 650-660℃, the oven pile cold or into the insulation pit slow cooling. Metallographic structure meets the requirements: pearlite structure of 2.5-6, with about 4 level as the best, the process improves the efficiency of 80%-100%

Typical example

1, can be used for ordinary abrasive spring steel

2, cold punching die

3, can be used for plastic mold, die-casting mold overall quenching rod steel.

Pickling process

The pickling treatment of 65Mn low alloy round steel is widely used to remove the surface oxide scale of cold rolled sheet metal billets, i.e. hot rolled sheet. For example, the surface treatment of hot rolled 65Mn low alloy round steel needs to be phosphating or coating to remove the oxide scale before processing. Surface pretreatment of welded pipes before galvanizing or other hot dip plating or electroplating; Annealed steel such as pipes, 65Mn low alloy round steel, wire and other cold drawing before the surface treatment; Steel work pieces are treated for plating, rust removal before brush plating, and similar treatment in the production of stainless steel and special steel. At present, pickling is still an indispensable process in the production of 65Mn low-alloy round steel and steel surface treatment. However, the adoption of the pickling process of 65Mn low-alloy round steel also brings some problems as follows:

[1] A large amount of 65Mn low-alloy round steel materials and acids are consumed

In the pickling process, some mainly through the chemical reaction of acid and iron sheet, dissolve the corresponding 65Mn low alloy round steel oxide dissolution to remove the iron sheet. Some, such as the use of sulfuric acid for pickling 65Mn low-alloy round steel, but also with the help of acid and 65Mn low-alloy round steel chemical reaction produced by the stripping of hydrogen bubbles to remove the oxide sheet. Therefore, in the pickling process, a large amount of acid consumption is inevitable. Although the use of pickling corrosion inhibitor in pickling can reduce the metal consumption of 65Mn low-alloy round steel, there is still a considerable amount of metal iron loss.

[2] The physical properties of 65Mn low-alloy round steel may be reduced

During pickling, a chemical reaction occurs between 65Mn low-alloy round steel and the acid and produces hydrogen gas. Because the chemical level of hydrogen in the pickling solution is higher than the chemical level of hydrogen in the pickling 65Mn low-alloy round steel, the generated hydrogen will penetrate into the steel and accumulate to cause hydrogen embrittleness, thus affecting the mechanical properties of the 65Mn low-alloy round steel or the subsequent processing.

[3] It will bring a series of environmental pollution problems

The surface treatment of 65Mn low-alloy round steel or parts is carried out by pickling process. Due to the different varieties, product specifications and production scale of 65Mn low-alloy round steel, there are great differences in production equipment and production environment. Such as the sealing of the pickling tank, the corrosion of the production equipment, the ventilation and exhaust of the pickling workshop, the discharge and treatment of acid fog, and the treatment and discharge of sewage, the treatment methods and treatment levels differ greatly. This will bring many environmental protection problems, and need to be dealt with and solved one by one.

[4] Waste acid and iron salt treatment problems

The pickling of 65Mn low alloy round steel consumes a large amount of metal iron, but also produces a large amount of waste acid and corresponding acid and iron oxide or iron salt solution. In order to recover and use these waste acid and iron salts, a large investment is needed to build the corresponding recovery and treatment equipment. Especially for some small, small batch of 65Mn low-alloy round steel pickling treatment, it is often difficult to concentrate the pickling waste liquid for treatment, once direct discharge occurs, it will cause serious pollution to the environment.