- Jun 06, 2017 -
Tension spring characteristics: a stretch limit buckle
Tension spring use: to prevent the pulse electronic fence front due to thermal expansion and contraction caused by alloy wire breakage and too loose
Tension spring Mounting quantity: Number of terminal rods * 2 * Number of mounting (eg four lines, eight lines)
Product content: When the tension reaches 10kg when the tension spring is no longer stretched, the alloy line drawing.
The choice of tension spring material should be determined according to the nature of the load of the tension spring, the stress state, the stress size, the working temperature, Tension Spring the environment medium, the service life, the requirements of the conductive magnetization, the process performance, the material source and the price.
In determining the shape and size of the material cross-section, should be preferred to the national standards and ministerial standards set by the series size, try to avoid the use of non-standard series of specifications of the material.
1. Medium and small tension springs, especially the spiral tension tension spring, should be given priority with the steel wire, lead bath and other cold cold drawn steel wire and oil quenched and tempered steel wire, with high strength and good surface quality, Tension Spring fatigue performance Higher than ordinary quenching and tempering steel wire, simple processing, process is good, stable quality.
2. Carbon tension spring steel wire and piano wire after cold drawing produce a greater residual stress, after processing tension spring, there is a large residual stress, tempering after a larger change in size, it is difficult to control the dimensional accuracy. Oil quenched and tempered steel wire is in the wire is drawn to the specified size of the wire after the modulation and strengthening treatment, Tension Spring basically no residual stress exists, after forming the tension spring by low temperature tempering, small change in size, heat stability is better than cold Pull the steel wire.
3. Large and medium tension spring, Tension Spring for the load accuracy and high stress should be used cold drawn or cold drawn polished steel. For the load accuracy and stress lower tension spring, hot rolled steel can be used.
4. Steel tension spring generally use 55Si2Mn, 60Si2MnA, 55SiMnVB, 55SiMnMoV, 60CrMn, 60CrMnB grades such as flat steel.
5. Spiral tension spring material cross-section, should be preferred circular cross-section. Square and rectangular cross-section material, bear a strong ability, good impact resistance, but also make the tension spring miniaturization, but the material source less. And the price is higher, in addition to special needs, the general try not to use this material. In recent years, the development of round steel wire rolling instead of trapezoidal wire, and achieved good results.
Tension spring material working at high temperature requires strong thermal stability, anti-relaxation or creep ability, resistance to oxidation, resistance to certain medium corrosion resistance Tension spring working temperature rise, tension spring material elastic modulus Down, Tension Spring resulting in decreased stiffness, load capacity becomes smaller. Therefore, the tension spring working at high temperatures must understand the rate of change (modulus) of the elastic modulus and calculate the effect of the decrease in the load carrying capacity of the tension spring on the performance. According to GB1239, the common spiral tension 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-working temperature t under the shear Modulus; Kt-temperature correction factor is selected according to Table 2-98.
The use of tension spring materials at low temperatures should have good low temperature toughness. Carbon tension spring steel wire, piano wire and 1Cr18Ni9 and other austenitic stainless steel tension spring steel wire, copper alloy, nickel alloy has good low temperature toughness and strength; at low temperatures, the brittleness of the material is very sensitive to surface defects, The surface quality should be strictly required; at low temperatures, the environmental medium is much less corrosive to the material than in the greenhouse, while the cadmium and galvanized easily lead to crisp; at low temperatures, the material's modulus of elasticity and expansion coefficient change little , In the design can not be considered.
Tension spring steel produced by the tension spring, hardness (ie, strength) of the selection should be based on tension spring bearing nature and stress size. However, the relationship between hardness and plane strain fracture toughness is great. Tension spring selection, we should pay attention to the hardenability of steel. Tension spring material section is quenching and quenching the degree of tension on the quality of a great relationship between the spring.
Tension springs with torsion springs themselves as conductors or tension springs, Tension Spring such as water (including seawater), in a water vapor environment, are generally made of copper and gold.