I. Introduction of 20# steel plate

20# steel plate belongs to high quality carbon structural steel plate, the thickness range is 3-200mm, the implementation of GB/T711-2008 and Q/WTB007-2008, the delivery state is hot rolling, normalizing, tempering, normalizing and tempering, annealing.

Two, 20# steel plate implementation standard and 20# steel plate delivery status

The implementation standard of 20# steel plate with thickness of 3-60mm is GB/T711-2008. The delivery state is hot rolled, and it can also be heat treated (normalizing, annealing, high temperature tempering).

The thickness & gt; The implementation standard of 60 to 200mm 20# steel plate is Q/WTB007-2008, and the delivery state is normalizing, tempering, normalizing and tempering, annealing. After negotiation by both sides of supply and demand, it can also be delivered in hot rolling state.

Three, 20# steel plate use

20# steel plate is suitable for manufacturing cars, tractors and general machinery manufacturing industry in the construction of small and medium-sized carburizing carburizing parts, such as car brake shoes, lever shaft, transmission fork, transmission passive gear and tractor camshaft, hanging equalizer shaft, equalizer bushing inside and outside; In hot rolling or normalizing state used for manufacturing force is not large, but requires high toughness of various mechanical parts; In heavy and medium machinery manufacturing, such as forged or pressed ties, carabiners, levers, sleeves, fixtures, etc. Used in steam turbine and boiler manufacturing industry for pressure ≤6N/ square, temperature ≤450℃ in the work of non-corrosive medium pipes, flanges, header and various fasteners; Used for making crosshead, piston and other castings on railway and locomotive. Normalizing can promote the spheroidization of the steel, refine the massive pre-eutectoid ferrite, and improve the cutting performance of the blank less than 160HBS.

Chemical composition of 20# steel plate, mass fraction % (melting analysis)

Thickness /mm C Si Mn P S Cr Ni Cu

3-600-17-0.230.17-0.370.35 - or less 0.650.0350.0350.200.300.25

60- 200> 0.17-0.240.17-0.370.35-0.650.0250.0200.250.250.25

Note: 1. If the supplier can guarantee the content of residual elements Cr, Ni and Cu in table 20# steel, it can not be analyzed;

2. The allowable deviation of chemical composition of finished steel plate shall conform to the provisions of GB/T222.

5. Mechanical properties of 20# steel plate

Thickness /mm Tensile strength MPa Elongation after fracture A/%180° cold bending test

Nominal thickness of steel plate A /mm Longitudinal V-shaped impact absorption energy KV2/J

3-60 Hot rolling or heat treatment is not less than or equal to 20> 20-6020 ℃ ~ 20 ℃

41028 d = AD = 2 a p of 27 or higher

> 38022-60-200 hot rolling

Note: 1. Heat treatment means normalizing, annealing or high temperature tempering;

2. When the 20# steel plate is delivered in heat treatment condition, when the elongation is increased by 2% (absolute value) compared with the above table, the allowable tensile strength of the 20# steel plate with thickness of 3-60mm is reduced by 40MPa compared with the above table, thickness > The 60-200mm 20# steel plate tensile strength is allowed to reduce 20MPa;