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- home > Supply > Bolt specifications | bolt | Baidu recommend quality brands - Yongnian standard parts Suketomo
Information Name: | Bolt specifications | bolt | Baidu recommend quality brands - Yongnian standard parts Suketomo |
Published: | 2013-11-20 |
Validity: | 0 |
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Detailed Product Description: | High strength bolts before plating process wire rods - (cold call) - ball (softening) Annealing - mechanical descaling - pickling - cold call - cold forming - thread processing - heat treatment - test [1] 1, steel Design in the fastener manufacturing. Correct selection of materials is an important part of the fastener because fasteners performance and the material has a close relationship. If improper or incorrect material selection may cause performance below standard, shortened life, and even accidents or processing difficulties, higher manufacturing costs, so the fastener material selection is a very important part. Cold heading steel is produced by cold forging technique interchangeability of higher steel fasteners. Because it is at room temperature using metal plastic molding, a large amount of deformation of each part, bear the strain rate is also high, so high strength bolts machining, cold heading steel raw materials for the performance requirements are very stringent. In the long-term production practice and user research, based on the combination of GB/T6478-2001 "cold heading and cold extrusion of steel technical conditions" GB/T699-1999 "quality carbon structural steel" and target JISG3507-1991 "cold heading steel with carbon steel wire rod, "the characteristics of a 8.8, 9.8 Bolts material requirements, for example, the determination of various chemical elements. C content is too high, cold forming properties will be reduced; too low, can not meet the requirements of the mechanical properties of parts, so as 0.25% - 0.55%. Mn steel can improve the permeability, but adding too much will strengthen the matrix organization and affect cold forming properties; in parts quenched austenite grain growth when there is a tendency to promote, so in an appropriate increase on the basis of international, fixed 0.45% - 0.80%. Si can be strengthened ferritic promote degradation cold forming, the material elongation decreased as 0.30% or less Si. SP is the impurity element bolt, their presence along the grain boundary segregation, resulting in grain boundary embrittlement and damage the mechanical properties of steel, should be reduced as far as possible, be less than or equal to P 0.030%, S 0.035% or less. B. Maximum is 0.005 percent boron, because boron steels, while having significantly improved permeability and other effects, but will also lead to increased brittleness of steel. Boron content is too high, for bolts, screws and studs such needs good mechanical properties of the workpiece is very unfavorable. Bolt drawing process: drawing process has two purposes, first, the size of the restructuring of raw materials; Second, the role of the fastener through the deformation strengthening access to basic mechanical properties, for carbon steel, alloy steel and carbon one purpose, that is, the disk of sheet obtained after controlled cooling cementite in the drawing process as much as possible of the crack for the subsequent ball (softening) granular cementite annealing to get ready, however, some manufacturers To reduce costs, any reduction Drawing times, excessive reduction rate increased wire rod hardening tendency, which directly affect cold heading steel wire rod performance. If the pass is inappropriate reduction rate distribution, but also make the wire rod produced in the drawing process in reverse cracks, this bolt longitudinal distribution along the wire manufacturers, a predetermined period of cracks in the wire exposed during the cold forging. In addition, the process of drawing such as poor lubrication can also cause cold drawn steel wire rod transverse cracks occur regularly. Steel wire rod wire die out on the grain volume while the tangential direction with different heart drawing dies, drawing dies unilateral will cause increased wear and tear bolt hole size, so that the hole out of round, causing deformation of the wire drawing circumferential direction uneven, so that the wire roundness tolerance, in the process of cold heading steel wire cross-section stress uneven impact of cold heading yield. Rod wire drawing process, the excessive part of the reduction rate of the wire surface quality deterioration, while the low reduction rate is not conducive to flake cementite broken, difficult to obtain as much granular cementite that cementite spheroidization rate is low, the performance for cold heading steel wire is extremely unfavorable, using drawing methods produce steel bars and wire rods, some reduction of 10% in the control plane straightforward - 15% range. If you have any questions about this information or advice, please contact us now! Our Company Name: Wu'an Suketomo Standard Parts Manufacturing Co., Ltd. (http://www.zhuyoubzj.com) Contact: Hao Bao yuan, or click on "Commercial Union Service" direct dialogue with us now! |
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Copyright © GuangDong ICP No. 10089450, Wu'an Suketomo Standard Parts Manufacturing Co., Ltd. All rights reserved.
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You are the 29664 visitor
Copyright © GuangDong ICP No. 10089450, Wu'an Suketomo Standard Parts Manufacturing Co., Ltd. All rights reserved.
Technical support: ShenZhen AllWays Technology Development Co., Ltd.
AllSources Network's Disclaimer: The legitimacy of the enterprise information does not undertake any guarantee responsibility