Kunshan automotive spring timber and development

Kunshan automotive spring timber and development

(1) the development of spring steel production process In order to improve the quality of spring steel, industrialized countries have been using the ordinary furnace refining technology, continuous casting process, a new type of rolling and on-line automatic detection and control equipment.

In order to ensure the chemical composition of steel, reduce the content of gas and various non-metallic inclusions, adopt large-capacity electric furnace or converter smelting, adopt ladle ladle refining to reduce the oxygen content (0.0021 ~ 0.0010)%, Production of ultra-pure steel, which greatly improved the design and work of the spring stress.

Continuous casting production process in spring steel production has been widely used. Continuous casting can reduce the segregation of steel by electromagnetic stirring, low temperature casting and other techniques to reduce secondary oxidation, improve surface decarburization, and make the structure and performance stable and even.

The use of sub-type continuous rolling mill, can improve dimensional accuracy, surface quality, but also make the steel microstructure along the length of uniform. In the rolling process in order to ensure the quality of the product surface using online automatic detection and control. In order to adapt to the production of variable-section spring flat steel, a new process of austenite rolling and forming has been developed, that is, the steel is first heated to the austenite zone and then quenched to the metastable austenite zone for plastic processing and quenching. This process allows the steel to increase strength without reducing ductility. In addition there are through rolling after the heat treatment and surface hardening treatment to improve the performance of spring steel.

(2) the development of alloy steel The main role of alloying elements is to improve the mechanical properties, improve process performance and give a special performance. Valve springs and suspension springs have been widely used SiCr steel. Si is the best alloying element to resist stress relaxation. Adding V and Mo into SiCr steel to form SiCrV and SiCrMo steel can improve fatigue life and anti-relaxation performance. At the same time SiCr drawing wire, its anti-relaxation performance when working at high temperature, than the piano wire and important use of carbon spring wire is better. With the engine speed miniaturization, anti-flutter performance, light weight, small modulus of elasticity of the Ti alloy has been more widely used, its strength up to 2000 MPa. Kunshan spring

(3) Development of Low-carbon Austenitic Steels Low-carbon austenitic steels 38SiMnB is a new type of high-performance spring steel independently developed in China. On the basis of this, 38SiMnVBE has advantages of high strength and toughness, high quenching Permeability, high applicability and high performance ratio. Tensile strength = (2030-2140) MPa, yield strength = (900-2010) MPa, elongation = (12-15)%, reduction of area = (48) after ultrafine grained controlled rolling ~ 55)%. It provides high-performance materials for the small pieces of variable section panel springs.

Battery spring

(4) Development of Stainless Steel China is a big country that produces stainless steel. With the development of stainless steel production, many varieties have naturally been developed. Up to now, more than 50 kinds have been developed, basically meeting the needs of domestic production and development. Some of the current developments New varieties for a brief description.

 1) The initial formation of austenitic stainless steel system. In order to eliminate carbon element caused by the corrosion of stainless steel grain boundary corrosion, the development of low-carbon austenitic stainless steel 0Cr18Ni9 and 00Cr17Ni2Mo2. In order to improve its special properties can be added Cu, Ti, Nb, Mn, Cr, Si and N and other elements.

 2) the development of nitrogen-containing stainless steel. Nitrogen carbon in stainless steel achieved results. N and C have many common features in austenitic stainless steels. N stabilizing the role of austenite than Ni, and C quite. N combines with Mn to replace the more expensive Ni.

N is also one of the most effective solid solution strengthening elements in austenite. The affinity between N and Cr is smaller than the affinity between C and Cr, and the precipitation of Cr2N is rare in austenitic steel. Therefore, N can improve the strength of stainless steel without reducing the corrosion resistance.

 3) the development of super ferritic stainless steel. Ferritic stainless steel with good corrosion resistance and oxidation resistance, its anti-stress corrosion resistance than austenitic stainless steel. The price is cheaper than austenitic stainless steel. However, there is a disadvantage of poor solderability and brittleness tendency, and the production and use are limited. By reducing the content of carbon and nitrogen in the steel, adding stabilizing elements such as Ti, Nb, Zr and Ta, and adding toughening elements such as Cu, AI and V to toughen the elements, the weldability of the ferritic steel can be improved Sexual and brittle.

4) the development of super austenitic steel. Super austenitic steel refers to Cr, Mo, N content was significantly higher than the conventional stainless steel austenitic steel. One of the more famous is the steel with 6% Mo (245S Mo). This type of steel has very good resistance to localized corrosion and has good pitting resistance (PI 40) and good stress corrosion resistance under seawater, aeration, presence of cracks and low-velocity scouring, Titanium alloy alternative materials.

5) the development of super martensitic stainless steel. The traditional martensitic stainless steel 2Cr13, 3Cr13, 4Cr13 and 1Cr17Ni2 lacks sufficient ductility, and is very sensitive to the stress during cold forging deformation, and cold forming is more difficult. Coupled with the relatively poor weldability of steel, the use of limited. To overcome the above shortcomings of martensitic steel, an effective approach has recently been found to develop a new series of alloy steel, super martensitic steel, by reducing the C and Ti content of the steel and increasing the Ni content. Such steel high tensile strength, good ductility, welding performance has also been improved, so martensitic steel, also known as soft martensitic steel or weldable martensitic steel.

(5) the development of spring wire Spring steel wire after 100 years of development, process technology experienced by the quenching of lead to oil quenching, now also developed to induction heating quenching. Together with continuous innovation and improvement of technology and equipment, the quality of varieties is continuously updated. The recent development of the valve spring steel induction heating quenching and tempering treatment, the experiment shows that, due to induction heating time is short, quenching small, almost no decarburization steel wire layer, so its plasticity, toughness, anti-relaxation, fracture toughness, Delayed fracture resistance, fatigue life than quenching and tempering of steel wire has greatly improved.

Another kind of ultrafine grained heat-treated steel wire has been successfully applied in the field. Ultrafine grained heat treatment is a kind of composite toughening technology combined with superfine microstructure and thermomechanical treatment. It can improve the mechanical properties of steel wire, while improving the surface quality of steel wire. The surface quality of the material has a great influence on the fatigue properties. In order to ensure the surface quality, stripping process for the special requirements of the material, the surface removed 0.1mm. Eddy current flaw detection on 0.5mm depth defects. Uneven surface of the wire drawing process, available electrolytic grinding, the surface roughness down to = (6.5 ~ 3.4) m.

(6) The development of stainless steel wire In recent years, foreign stainless steel wire spring production has developed rapidly. The domestic demand increased varieties are mainly 1Cr18Ni9 and 0Cr17Ni7AI.

The advanced steel wire production process is characterized by the first stripping of the wire rod to remove the defects caused by the hot working on the surface. In addition to the pickling after the first solution treatment, the entire cold working process maintains a bright surface.

With the development of technology, stainless steel wire production process to further simplify, part of the original metal products industry quality control simplified, converted to the quality requirements of the wire rod. After the rough drawing machine, clean ball cleaning and water cleaning, remove the surface coating and residual lubricating film. Equipped with electrolytic pickling, alkali neutralization, water rinsing and drying equipment before the bright heat treatment to completely remove the oil on the steel wire surface and improve the surface quality.

(7) Development of shape memory alloy At present, there is a promising one-way shape memory alloy for the spring, and the best performance is 50Ti and 50Ni. Spring made of shape memory alloy is telescopable by temperature. Mainly used for constant temperature, constant load, constant deformation of the control system. Because it is by spring telescopic actuator, so the work of the spring stress changes.

(8) Ceramic Applications Ceramic high modulus of elasticity, low breaking strength, suitable for deformation of small places. Currently under development are heat-resistant, wear-resistant, good insulation ceramics, the application of superplastic zinc alloy (SPZ), at room temperature with high strength. In addition, there are high-strength silicon nitride, high temperature, up to 1000 ℃. However, ceramic springs are not suitable for operation under impact load.

(9) Application of Fiber Reinforced Plastics in Springs Glass-fiber reinforced plastic (GFRP) leaf springs have been widely used in Britain, the United States, Japan and other countries. In addition to being used for transverse suspension, they can also be used in special light vehicles, such as the vertical Set the suspension. Has also successfully developed a carbon fiber reinforced plastic (GFRP) suspension spring, lighter than the metal leaf spring 20%. Kunshan extension spring