First, the material requirements of bolts, screws and studs (GB/T3098.1-2000) Performance level Materials and heat treatment chemical composition,% Tempering temperature C P S B1) Min Max 3.62) Carbon steel —— 0.20 0.05 0.06 0.003 —— 4.62) —— 0.55 0.05 0.06 0.003 —— 4.82) 5.6 0.13 0.55 0.05 0.06 0.003 —— 5.82) —— 0.55 0.05 0.06 6.82) 8.83) Low carbon alloy steel (such as boron, manganese or chromium), quenched and tempered or medium carbon steel, quenched and tempered 0.154) 0.04 0.035 0.035 0.003 425 0.25 0.55 0.035 0.035 9.8 Low carbon alloy steel (such as boron, manganese or chromium), quenched and tempered or medium carbon steel, quenched and tempered 0.154) 0.35 0.035 0.035 0.003 425 0.25 0.55 0.035 0.035 10.95), 6) Low carbon alloy steel (such as boron, manganese or chromium), quenched and tempered 0.154) 0.35 0.035 0.035 0.003 340 10.96) Medium carbon steel, quenched and tempered or low, medium carbon alloy steel (such as boron, manganese or chromium), quenched and tempered or alloyed steel quenched and tempered 7) 0.25 0.55 0.035 0.035 0.03 425 0.20 0.55 0.035 0.035 0.003 10.96), 8), 9) Alloy steel, quenched and tempered 7) 0.28 0.50 0.035 0.035 0.003 380 1) The boron content can reach 0.005%, and the non-effective boron can be controlled by adding titanium and/or aluminum. 2) These performance grades allow for easy-cut manufacturing. The maximum levels of sulfur, phosphorus and lead are: sulfur 0.34%; phosphorus 0.11%; lead 0.35%. 3) In order to ensure good hardenability, the fasteners with a thread diameter exceeding 20 mm shall be steel specified in class 10.9. 4) The minimum content of manganese in low carbon alloy steel containing less than 0.25% carbon (barrel analysis) is: grade 8.8: 0.6%; grades 9.8, 10.9 and 10.9: 0.7%. 5) The product should be marked with a horizontal line under the performance level code. Class 10.9 shall comply with all performance requirements specified in Class 10.9, while lower turbulence temperatures will cause varying degrees of stress reduction at elevated temperatures. 6) The material used for this performance grade should have good hardenability to ensure that the core of the fastener thread section obtains about 90% of the martensite structure after quenching and before tempering. 7) The alloy steel shall contain at least one of the following elements: the minimum content is: chromium 0.30%; nickel 0.30%; molybdenum 0.20%; vanadium 0.10% 8) Considering the tensile stress, the surface of the 12.9 grade is not allowed to have a white phosphorus aggregate layer that can be measured by the metallographic phase. 9) The chemical composition and tempering temperature are still under investigation. Concerned about surprises Label: Material requirements for bolts, screws and studs of the Knowledge Lecture Hall Previous: Fuel-saving performance of electric power steering (EPS) and next: Mechanical common sense 30 questions common problems of mechanical common sense and * Plate FLANGE (Plate Flange, Flat Flange, Plain Flange) Blank Flanges,BS4504 Blank Flange,DIN 2527 Blank Flanges,Steel Blank Flanges Shandong Zhongnuo Heavy Industry Co.,Ltd. , https://www.zhongnuoflanges.com
°C
Min
Max
Max
Max
0.204)
0.55
0.035
0.035 
* SLIP ON FLANGE (SORF SOFF FLANGE)
* WELDING NECK FLANGE (WNRF FLANGE)
* BLANK FLANGE (BLIND FLANGE, BLFF FLANGE, BLRF FLANGE)
* THREADED FLANGE (SCREWED FLANGE)
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