Application of steel 20X13
Steel 20X13 is used in the manufacture of products for work in mildly aggressive environments:
- atmospheric conditions, except sea;
- aqueous solutions of organic acid salts at room temperature;
- solutions of nitric acid of weak and medium concentration at moderate temperatures, etc..
Steel 20X13 is used in those cases, when products must have a sufficiently high strength, as well as high plasticity and toughness. Steel 20X13 welds satisfactorily.
Steel 20X13 is also used as a heat-resistant material at temperatures up to 450-550 °With and as heat-resistant - up to 700 °FROM.
Chemical composition of steel 20X13
Steel 20X13 is included in steels of type X13 together with steels 08X13, 12Х13, 30X13 and 40X13. It occupies its own range in terms of carbon content - from 0,16 to 0,25 %, the amounts of other alloying elements and impurities are the same, like other steels of type X13 (table 1).
According to the GOST classification 5632-72 steel 20X13 belongs to the martensitic class.
Transformations and microstructure of steel 20X13
- When heated annealed steel 20X13 polymorphic alpha-gamma transformation in it occurs in the temperature range from 820 °FROM (As1) to 950 °FROM (As3). Temperature points Ar1 is 780 °FROM.
- With isothermal holding or slow cooling in the interval 800-550 °Ferrite-carbide mixture decomposes with austenite. This ferrite-carbide mixture is composed of high chromium ferrite and Cr type carbide23C6.
- Upon rapid cooling of 20Kh13 steel, a martensitic transformation occurs in it. The temperature of the onset of martensitic transformation - 220 °FROM.
- With an increase in the tempering temperature, there is a significant decrease in strength with an increase in ductility, as well as a decrease in corrosion resistance.
Steel assortment 20X13
The following products are made from 08X13 steel:
- thick sheet according to GOST 7350-77;
- thin sheet according to GOST 5582-75;
- tape and roll according to GOST 4986-78;
- long products according to GOST 5949-75;
- hot-deformed pipes according to GOST 9940-81;
- cold-deformed and heat-deformed pipes in accordance with GOST 9941-81;
- wire according to GOST 18143-72.
Mechanical properties of steel 20X13
The mechanical properties of steel 20X13 in various types of products are presented in the table 2.
Influence of lowering and increasing temperature on the mechanical properties of a 20X13 steel bar after normalization with 1000-1020 °With and leave at 730-750 °C shown in the table 3.
Steel 20X13 has high resistance to atmospheric conditions (except for the marine atmosphere), river and tap water.
Special properties of steel 20X13
For details, operating at elevated temperatures for a long time, limiting operating temperature is 450-475 ° C, for short-term work - 500-550 ° C.
Density of steel 20X13 - 7,76 g / cm3.
Welding of steel 20X13
Steel 20X13 is satisfactorily welded by electric and argon-arc automatic and manual welding.
Heat treatment of welded seams of steel 20X13
After welding, tempering of welded joints or products is carried out. Tempering temperature depends on the level of required mechanical properties. Most often, leave is used when 680-760 °FROM.
Technological parameters of steel 20X13
Steel 20X13 has good workability in hot plastic deformation. The temperature range of hot plastic deformation is from 1100 to 875-950 °FROM. Heating for rolling and forging up to 780 °S spend slowly. After hot deformation, slow cooling is applied.
For 20Kh13 steel, softening annealing is usually used at 750-800 °With cooling in an oven to 500 °FROM. Final heat treatment - hardening with 950-1000 °With cooling in oil or air and tempering to the specified hardness and corrosion resistance.
Ульянин Е. A. Corrosive steels and alloys, 1991.
Gulyaev A. P. Metallurgy, 1986.