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Henan Friend Metal Products Co.,Ltd

Oil quenching - tempering wire products Introduction

Some of the special wire products in the final need to use in the quenching - tempering state, the traditional approach is to provide cold-drawn or annealed metal products, steel wire, the downstream enterprises will be made of the corresponding parts or components, and then quenching + Fire treatment, strength and toughness to meet the required requirements after delivery. Because the size of components or components, the ever-changing shape, bringing the final heat treatment furnace vary widely, will inevitably lead to increased production costs, heat treatment performance increased. Now gradually evolved into: the shape is not complicated, easy to shape the parts or components with steel wire quenching + tempering transfer to the metal products factory, which formed a new species: quenching - tempering wire.


Oil quenching - tempering treatment: refers to the drawing to the finished size of the wire, in a continuous furnace for quenching and tempering treatment, the first start in the continuous heating furnace wire to the full austenitizing temperature, and then obtained by oil tank quenching Martensite, and then through the continuous furnace tempering, to obtain the desired strength and toughness. Oil quenching - tempering wire flatness is good, the mechanical properties of uniformity, made of parts or components only after the low temperature to eliminate stress treatment that can be used directly.

Oil quenching - tempering heat treatment furnace by the tension line device, heating furnace, oil quenching tank, tempering furnace and the collection of five parts. Commonly used in carbon spring steel wire, alloy spring steel wire, elastic needle cloth wire, alloy steel wire and martensitic stainless steel wire and other finished heat treatment, heat treatment after the microstructure of the wire is usually tempered martensite, Tempered sorbite, with high strength (hardness), suitable toughness and good straight properties.

Pre-hardening treatment: is a special oil quenching - tempering treatment, refers to the wire drawing to the finished product size after the oil quenching treatment, and then according to the grade and use, and then one or more high temperature tempering treatment, so that the wire Hardness or tensile strength to meet the requirements of the corresponding level. Commonly used in cold work die steel wire, hot die steel wire and plastic mold wire and other finished heat treatment. Because such steel wire and alloy elements content is high, oil quenching - tempering must adopt some special process measures:

① in order to ensure the full dissolution of carbon and alloy elements, we must improve the austenitizing heating temperature (some up to 1150 ℃), to extend the holding time;

② quenched steel wire retained a large amount of austenite, in order to promote the decomposition of the debris to ensure that the wire to achieve the desired hardness, must use multiple tempering method, the tempering time than the general tempering to extend several times to hundreds of times.

③ general quenching - tempering treatment, the purpose of tempering is to promote the transformation of martensite martensite, tempered martensite, tempered sorbite or pearlite, after tempering steel toughness and plasticity Significantly increased, but the tensile strength and hardness must have a different range of decline. In the pre-hardening treatment, the tempering also has the purpose of promoting the transformation of the structure, but also has the precipitation hardening effect, the Fe, Mn and the alloying elements (Cr, Mo, Ti, V, W ,, Al, etc.) , Nitride or intermetallic compounds (γ 'and γ' 'phase) precipitation, the wire can be done in the toughness and plasticity significantly improved at the same time, tensile strength and hardness did not significantly decreased, or even improved.

The special process requirements determine the pre-hardened equipment and the general (spring steel) oil quenching - tempering equipment is very different: spring wire is usually used continuous furnace for oil quenching - tempering treatment, quenching furnace maximum temperature 900 ℃, The maximum temperature of the furnace is 600 ℃ and the furnace length is relatively short. Hardening treatment of quenching and tempering usually also use continuous furnace, but the furnace maximum temperature and furnace length are greatly improved. At present, the world's advanced level of pre-hardening furnace, quenching furnace maximum temperature 1150 ℃, the effective heating zone length 22m; tempering furnace maximum temperature of 700 ℃, the effective heating zone length of 30m. In addition, the retractor system can apply a certain, adjustable pre-tension to the wire to improve the creep resistance and stress relaxation resistance of the wire.

In general, the pre-hardening furnace can be used for oil quenching-tempering treatment, but the oil quenching-tempering furnace can not be used for pre-hardening treatment. The greater difference is that the pre-hardening treatment is usually carried out for 2 or more tempering. The tempering holding time is calculated in hours and can not be completed in a continuous furnace. It needs to be carried out in a periodic annealing furnace. Configuration of different specifications of the cycle of gas protection annealing furnace for the development and development of such wire lay the foundation.

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