Q390B alloy steel plate introduction and industrial application Q390B spot
Q390B high-temperature alloy steel plate introduction and industrial application
Q390B steel plate introduction:
Q390B is a low-alloy high-strength plate, with good fatigue resistance, high toughness and low brittle transition temperature. It is mainly used for all kinds of construction machinery, plant construction and general construction. Q390B steel plate has low carbon content and cannot be quenched and tempered, but it has excellent corrosion resistance and wear resistance, and can be used in loaders, bulldozers and coal mine hydraulic supports and other mechanical equipment and other structural parts
Q390B, Q390BL, Q390BL1 steel plate, where S is the meaning of structural steel, Q means that the impact temperature of the steel plate is -20 °C, then QL means that the impact temperature of the steel plate is -50 °C, then guess what, what does QL1 represent, QL1 means that the impact temperature of the steel plate is -60 °C, and 460 means the thickness of £ 50mm The minimum yield strength value is specified.
| Chemical composition |
| Tabulation: Depu Steel Date: 2024-01-18 |
| C |
Mn |
Si |
P |
S |
V |
Nb |
Ti |
| ≤0.20 |
1.00-1.60 |
≤0.55 |
≤0.030 |
≤0.030 |
0.02-0.20 |
0.015~0.060 |
0.02~0.20 |
Note:
(1): In order to improve the properties of steel, other trace alloying elements other than the above table can be added, and the data comes from the network and is for reference only.
(2): The allowable deviation of the chemical composition of the finished steel plate shall comply with the provisions of
GB/T222 Q390B steel plate mechanical properties: tensile strength σb (MPa): ≥695 yield strength σs (MPa): ≥410
elongation δ5
/(%):
≥11
section shrinkage ψ/(%) ):≥35
Steel Delivery Condition Hardness HBS 10/3000 : Untreated Steel ≤269 Annealed Steel ≤229
Recommended Heat Treatment/°C Normalized 810
Specimen Size: Sample Blank Size/mm: 25
Q390B Steel Plate Heat Treatment and Welding Performance Introduction
1. When welding electrode arc welding, for thin plates without beveling, E5015 (J507) and E5016 (J506) electrodes can be used for welding; For the thick plate with beveling, E5515 (J557) and E5516 (J556) flux should be used for welding.
2. When submerged arc welding, H08MnA welding wire can be used to weld with HJ431 or HJ430 flux for thin plates without beveling; For medium and heavy plates with open bevels, H10Mn2 or H10MnSi can be welded with HJ431 or HJ430 flux; For thick plates with deep grooves, H08MnMoA should be used for welding with HJ350, HJ250 or SJl01 flux.
3. As a high-strength welded structural steel, this kind of steel has a low carbon content, usually the mass fraction of carbon is less than 0.18%, and the requirements of weldability are also considered in the design of alloy composition, so the welding of low-carbon
quenched and tempered steel is basically similar to normalizing steel. The following problems
mainly occur during welding: 4. Thermal cracks in the weld and liquefaction cracks in the heat-affected
zone. Low-carbon quenched and tempered steel generally has a low carbon content, a higher manganese content, and a stricter control of S and P, so the tendency to crack is smaller, but the high-nickel and low-manganese type of low-alloy high-strength steel will increase the tendency of hot cracks and liquefaction cracks.
5. Cold cracks. Because this type of steel contains more alloying elements that can improve
hardenability, it has a great tendency to crack cold. But due to this type of steel M. The higher the point, if the joint can be cooled more slowly at that temperature, the resulting martensite has time to undergo a "self-tempering" process. The tendency to crack is reduced to a certain extent, so the tendency to crack is not necessarily very large in practice.
6. Reheat cracks. Low-carbon quenched and tempered steels contain strong carbide forming elements such as V, Mo, Nb, and Cr, so they have a certain tendency to reheat cracks.
