Suzhou spring manufacturers tell you the choice of spring material, should be based on the nature of the spring load, stress conditions, stress size, operating temperature, environmental media, life, the requirements of conductive magnetic conductivity, process function, material origin and price and other factors recognized. 

In recognition of the shape of the cross-section of the material and standards, should give priority to the national standards and ministerial standards of the rules of the series of standards, try to prevent the use of non-standard series of standard materials. 

Small and medium-sized springs, especially helical extension springs, should be given priority to steel wire after strengthening treatment, lead bath isothermal cold drawn steel wire and oil quenched and tempered steel wire, with high strength and excellent surface quality, fatigue function is higher than the general quenched and tempered steel wire, processing is simple, good workmanship, quality and stability. 

Carbon spring steel wire and piano wire cold drawn after the occurrence of large residual stress, processing spring, there is a large residual stress, tempered standard changes, difficult to control the standard accuracy. Oil quenching and tempering steel wire is in the steel wire is drawn to the rules of the standard modulation after strengthening treatment, basically no residual stress exists, molding springs after low-temperature tempering, the standard change is very small, heat-resistant stability is better than the cold-drawn reinforced steel wire. 

Large and medium-sized springs, on the load accuracy and stress should be selected after cold-drawn material or cold-drawn polished steel. On the load accuracy and stress lower spring, can choose hot rolled steel. 

Plate springs generally use 55Si2Mn, 60Si2MnA, 55SiMnVB, 55SiMnMoV, 60CrMn, 60CrMnB and other trademarks of flat steel.

The cross-section of the material of the coil spring, should give priority to the use of circular cross-section. Square and rectangular cross-section of the material, e-spring withstand capacity is stronger, good impact resistance, and can make the spring miniaturization, but the material comes from less. And higher prices, in addition to special needs, generally try not to use this material. In recent years, the development of round steel wire rolled flat instead of trapezoidal steel wire, achieved good results. 

Operating at high temperatures in the spring material, the strength required to have a good thermal stability, resistance to relaxation or creep, oxidation resistance, resistance to certain media corrosion ability. 

Spring operating temperature increases, the spring material modulus of elasticity decreases, resulting in a decrease in stiffness, bearing capacity becomes smaller. Therefore, in the high temperature operation of the spring must understand the modulus of elasticity of the rate of change (value), accounting for the spring bearing capacity to reduce the impact on the use of function. In accordance with the rules of GB1239, the general coil spring operating temperature exceeds 60 ℃, the shear modulus should be modified, the formula is: Gt = KtG where G - the elastic modulus at room temperature; Gt - operating temperature t under the shear modulus; Kt - - temperature modification factor according to Table 2-98 selected. 

Spring materials used in low temperatures, automotive interior springs should have excellent low-temperature resistance. Carbon spring steel wire, piano wire and 1Cr18Ni9 and other austenitic stainless steel spring steel wire, copper alloys, nickel alloys have better low temperature resistance and strength. 

At low temperatures, the material's brittleness to the surface shortcomings are very sensitive, therefore, the surface quality of the material should be strictly required. 

At low temperatures, the environmental media on the material corrosion than in the greenhouse under the degree of much smaller, and cadmium plating and galvanizing easy to cause cold embrittlement. 

At low temperatures, the modulus of elasticity and coefficient of expansion of the material does not change much, in the planning can not be considered. 

Spring steel made of spring, hardness (i.e., strength) selection should be based on the nature of the spring load bearing and stress magnitude. However, the hardness of the concave and convex and plane strain fracture resistance contact greatly. 

From the curve contact can be seen, with the increase in hardness, plane strain fracture resistance (KIC) value decreased significantly. That is to say in recognizing the hardness of the spring hardness value, should be in line with the premise of satisfying the spring characteristics, the spring hardness value of some of the lower good. 

Spring selection, pay attention to the hardenability of steel. Spring material cross-section is hardened and the degree of hardening, the spring quality contact greatly. 

To spring itself as a conductor of electrical appliances spring or in the humidity changes in the conditions, such as water (including seawater), water vapor environment, the spring, generally choose copper and gold materials. 

In the acid touch extreme other corrosive media operation of the spring, the general selection of stainless acid-resistant steel or nickel alloy and other corrosion-resistant materials. In the general environment of the media conditions used in the spring, the use of general spring steel, made of spring in its surface rust coating or plating (galvanized, cadmium-plated, copper-plated) method of corrosion prevention. 

In the scale and the surface of the spring, in order to satisfy its accuracy is not affected by temperature changes, the general choice of modulus of elasticity and expansion coefficient of change is very small constant elasticity alloy.