Commonly Used Fasteners Used Materials
First, the standard parts on the market today mainly include:
Carbon steel (including Easy iron and steel), Stainless steel (including free cutting stainless steel), Copper (including Fast cutting copper).
(a) Carbon steel. We distinguish low-carbon steels, medium-carbon steels and high-carbon steels, and alloy steels from the carbon content of carbon steel.
1. Low carbon steel C%≤0.25% Domestically known as A3 steel. Basically known abroad as 1008,1015,1018,1022 and so on. Mainly used for Grade 4.8 bolts and Grade 4 nuts, small screws and other products without hardness requirements. (Note: The drilled nail is mainly made of 1022 material.)
2. Medium carbon steel 0.25% <C% ≤ 0.45% Domestically known as No. 35 and No. 45 steels, and abroad basically referred to as 1035, CH38F, 1039, 40ACR, etc. Mainly used for 8 grade nuts, 8.8 bolts and 8.8 grade hexagonal products.
3, high carbon steel C%> 0.45%. Currently not used in the market
4, alloy steel: Adding alloying elements to plain carbon steel, Increase some special properties of steel: Such as 35,40 chrome molybdenum, SCM435, 10B38. Fang Sheng screws mainly use SCM435 chromium molybdenum alloy steel, the main components are C, Si, Mn, P, S, Cr, Mo.
(b) Stainless steel. Performance level: 45, 50, 60, 70, 80
Mainly divided into austenite (18%Cr, 8%Ni) good heat resistance, good corrosion resistance, good weldability. A1, A2, A4
Martensite and 13% Cr have poor corrosion resistance, high strength, and good wear resistance. C1, C2, C4 ferritic stainless steel. 18%Cr has better forging properties and is more corrosion resistant than martensite. Currently imported materials in the market are mainly Japanese products. According to the grade mainly divided SUS302, SUS304, SUS316.
(c) Copper. Commonly used materials for brass ... zinc copper alloy. The market mainly uses H62, H65, H68 copper as standard parts.
two, Material used for carbon steel products：
| Category | Optional materials |
| Pressure riveting fasteners | Quick cutting steel 12L14 1215 11L44 (turning type, such as type B SO type, DSO, etc.), SUS303, SUS304 (CLS, etc.), 10B21 (FH HFH, etc.) |
| Copper nut for injection molding | Quick-cut copper C3604 lead-free copper, stainless steel SUS303 |
| Grade 8.8 hexagon bolt | 1035ACR (below M10) 1040ACR (M12 or more) CH38F 1045ACR 1039 10B21 (mainly such) 10B33 10B38 |
| 8.8 Hexagon Socket Head Bolts | CH38F 1039 10B21（M10-M12） 10B33 （M14）10B38（M12-M24）10B21 |
| 10.9 Hexagon bolts | 1045ACR 10B38 |
| 12.9 level | alloy steel 35CrMo 40CrMo 42CrMo |
| │8│level nuts | 1008K 1010 |
| 8 level nuts | 1015(M<16) CH38F (M≥16) |
| Level 10 nuts | CH38F 1039 10B21 10B33 |
| 12 level nuts | 1039 10B21 10B33 10B38 |
| Carriage bolt | 1008 1010 1015 |
| Hex flange bolt | CH38F 1039 10B21 10B33 10B38 |
| Hexagonal wood screws | 1008K 1010 |
| Self-tapping screws and wallboard nails | 1018 1022 CH22A |
| Drilling nails, splint nails | |
| Machine screws. Furniture screws | 1008 1010 |
Third, the impact of various elements in the material on the nature of the steel:
1. Carbon (C): To improve the strength of steel parts, especially its heat treatment performance, but as the carbon content increases, the plasticity and toughness decrease, and it will affect the cold heading performance and welding performance of steel parts.
2, manganese (Mn): to improve the strength of steel, and to some extent improve the quenchability. That is, the strength of the hardened infiltration increases during quenching, and manganese can also improve the surface quality, but too much manganese is detrimental to ductility and weldability. It will also affect the control of plating during plating.
3, nickel (Ni): to improve the strength of steel, improve the toughness at low temperatures, improve resistance to atmospheric corrosion, and to ensure a stable heat treatment effect, reducing the role of hydrogen embrittlement.
4, chromium (Cr): can improve the hardenability, improve wear resistance, improve corrosion resistance, and help maintain strength at high temperatures.
5, molybdenum (Mo): can help control the quenchability, reduce the sensitivity of steel on temper brittleness, have a great influence on the tensile strength at elevated temperatures.
6. Boron (B): It can improve the hardenability, and it helps to make the low carbon steel heat treatment and produce the desired reaction.
7. Niobium (V): refines austenite grains and improves toughness.
8, silicon (Si): to ensure the strength of steel, the appropriate content can improve the plasticity and toughness of steel.
Fourth, on the characteristics of stainless steel profile (304,316)
(a) The three materials are all 300 series austenitic stainless steels and their chemical composition is as follows:
|
name |
C |
Si |
Mn |
P |
S |
Ni |
Cr |
Mo |
Cu |
|
304M |
≤0.06 |
≤1.0 |
≤2.0 |
≤0.045 |
≤0.03 |
8.91-10.0 |
18.0-20.0 |
0 |
0 |
|
316 |
≤0.03-0.06 |
≤1.0 |
≤2.0 |
≤0.045 |
≤0.03 |
10.0-14.0 |
16.0-18.0 |
2.0-3.0 |
0 |
|
304HC |
≤0.08 |
≤1.0 |
≤2.0 |
≤0.045 |
≤0.03 |
8.0-10.5 |
17.0-19.0 |
0 |
1.0-3.0 |
1. Carbon C can increase hardness and strength. Excessive content can reduce its ductility and corrosion resistance.
2, Chromium Cr can increase corrosion resistance, oxidation resistance, grain refinement, increase strength, hardness and wear resistance
3, Ni Ni can increase the high temperature strength, corrosion resistance, reduce the rate of cold work hardening
4, molybdenum Mo increases strength, excellent corrosion resistance to oxides and seawater
5, Copper Cu facilitates cold forming and reduces magnetic properties
