Q345E-Z25 is a grade of steel, belonging to low alloy high strength Z-shaped steel plate, with good low temperature impact performance; The grade of steel is composed of four parts: Chinese Pinyin letter representing yield strength, yield strength value, quality and Z-direction performance level symbol. Among them:
Q stands for yield strength;
345 indicates yield strength value, unit MPa;
E indicates grade (-40 degree impact);
Z25 Indicates the thickness direction (Z direction) performance level symbol.
Main performance
Z-direction steel: also known as "lamellar tearing resistant steel", that is, usually said Z-direction performance. In welded steel structures, when the thickness of the steel plate is not less than 40 mm and it is subjected to tension along the thickness of the plate, in order to avoid laminar tearing during welding, it is necessary to use laminar tearing resistant steel (usually referred to as "Z-steel"). The problem of lamellar tearing exists in thick plate, so the Z-direction performance test is proposed. The steel plate and the section steel are rolled and formed, and the steel used in the multi-high-rise steel structure is generally hot-rolled, which can destroy the casting structure of the ingot and refine the grain of the steel. The bubbles and cracks formed when the ingot is poured can be welded under high temperature and pressure, so that the mechanical properties of the steel can be improved. However, this improvement is mainly reflected in the rolling direction, because the non-metallic inclusions (mainly sulfides, oxides, silicates, etc.) inside the steel are pressed into sheets after rolling, and still remain in the steel plate (generally parallel to the surface of the steel plate), and the steel plate appears stratification (sandwich) phenomenon. This non-metallic interlayer phenomenon. Deterioration of the tensile properties of steel along the thickness direction. Therefore, the mechanical properties of the steel plate in three directions are different: the best along the rolling direction; The performance perpendicular to the rolling direction is slightly worse; In the direction of thickness, the performance is second. Generally, the thick steel plate is easier to produce laminar tear, because the thicker the steel plate, the more non-metallic inclusion defects, and the thicker the weld, the greater the welding stress and deformation. To solve this problem, it is best to use Z-directional steel. This steel plate is on the basis of a certain level of structural steel (called mother steel), after special smelting, treatment of steel, its sulfur content is less than 1/5 of the general steel, and the section shrinkage rate is more than 15%. The mechanical properties of the steel plate along the thickness direction (mainly ductility properties) are called Z-direction properties. The Z properties of steel plates can be obtained by tensile test of specimens, and are generally measured by section shrinkage. The mark of the Z steel plate produced in China is to add the Z steel plate grade mark Z25, Z25, Z25 behind the parent steel steel number, and the number behind the Z word is the index of the section shrinkage rate (%).
Application prospect
Construction machinery, shipbuilding, petrochemical, power plant construction, bridge construction and other manufacturing enterprises have cooperated with Wugang Jinyiquan Iron and Steel Company and Wugang to produce for ships, boilers, pressure vessels, oil storage tanks, Bridges, power plant equipment, lifting and transportation machinery and other high-load welding structural parts construction projects, the use of Q345E steel plate up to 900,000 tons. In the export of the United States, Canada, Australia, India, Europe is a promising prospect. Has directly supplied more than 20,000 tons to European customers. Wugang production technology leading. Wugang products are more in stock, if necessary, for 8mm-120mm-650mm thickness and widest to 3900mm. In particular, () signed a strategic cooperation agreement with Wuyang Iron and Steel Co., LTD., Hebei Iron and Steel Group.
Chemical composition
According to the new national standard GB/1591-2008, the chemical composition is as follows
Quality grade Chemical composition a b (mass fraction) /%
Q345ECSiMnPSNbVTiCrNiCuNMoBAls
0.18 0.50 or less or less 0.170.0250.0200.070.150.200.300.500.300.0120.10-0.015 or less
Mechanical property
According to the new national standard GB/T1591-2008, the mechanical properties are implemented as follows
Grade Thickness /mm Tensile strength Rm/Mpa(N/mm2) Yield strength ReL/Mp(N/mm2) Elongation A/% Impact test Temperature /℃ Impact absorption energy KV2/J180° Bending test Bending diameter Q345E
6~40470-63033521-4034d=2a>40~63470-63032520-4034d=3a>63~80470-63031520-4034d=3a>80~100470-63030520-4034d=3a>100~150450-6 0028519
34
> 150 ~ 200450-60027518
27
> 200 ~ 250450-60026518
27
> 250 ~ 400450-60026517
27
Common size
Experimental method
Inspection items, sampling quantity, sampling method and experimental method of each inspection
No. Inspection Item Quantity of samples/Sampling methods Test Method 1 Chemical composition (melting analysis) 1/ Furnace GB/T20066GB/T233, GB/T4336, GB/T201252 Tensile test 1/ lot GB/T2975GB/T2283 Bending test 1/ lot GB/T2975GB/T2324 Impact test 3/ lot GB/T2975GB/T2295Z section shrinkage in the direction of steel thickness 3/ lot GB/T5313GB/T53136 Non-destructive inspection sheet or piece by piece negotiation according to the non-destructive inspection standard 7 Surface quality sheet by piece - visual and measurement8 Size, shape sheet by piece - appropriate weight
Application field
Construction machinery, mining machinery, metallurgical environmental protection, water conservancy and hydropower, wind power and other structural parts.
