Steel 08KH18N12T (0Х18Н12Т)
|Designation GOST Cyrillic||08Х18Н12Т|
|Designation GOST Latin||08X18H12T|
|By chemical elements||08Cr18Н12Ti|
|Designation GOST Cyrillic||0Х18Н12Т|
|Designation GOST Latin||0X18H12T|
|By chemical elements||0Cr18Н12Ti|
08KH18N12T steel is used: for the production of cold-rolled sheets and strips high tensile strength; the various parts and structures, welded by spot welding; pipe and fabrication of welded equipment operating in environments of increased aggressiveness (the solutions of nitric, acetic acids, alkaline solutions and salts); structures to be welded by spot welding; hull structures of ships, vessels, marine equipment products and shipyards (pipelines, fittings, fairings, various instruments); hot-rolled seamless pipes machined and the machined designed for stoves and communications neftepererabativaushiy plants.
Low steel, corrosion-resistant.
Stabilized chromium-Nickel steel of austenitic class.
Magnetic permeability μ ≤ 1,01 GS/E. Steel usually contains the α-phase. Unfavorable balance of alloying elements and carbon magnetic permeability can be up to 1.50 GF/C. Heat treatment — austenization or stabilization, the hot pressure treatment and flexible at temperatures primenyaemyh for hot deformation do not alter the permeability, and hardening higher than 5−10% at room or lower temperatures significantly increases it.
Steel 08KH18N12T has practically no ferrite phase and has a high resistance to intergranular corrosion than steel 08KH18N10T.
Steel has low friction properties and prone to scuffing, so is not usually used in friction pairs. To improve the antifriction properties of the nitriding is performed under special conditions with the use of ammonium chloride to remove the oxide film.
|Test methods. Packing. Marking||В09||GOST 11878-66|
|Sheets and strips||В33||GOST 5582-75, GOST 7350-77|
|Classification, nomenclature and General rules||В30||GOST 5632-72|
|Steel pipes and fittings to them||В62||GOST 9940-81, GOST 9941-81, GOST 14162-79, TU 14-3-1109-82, TU 14-3-1120-82, TU 14-3-1556-88, TU 14-3-197-89, TU 14-3-561-77, TU 14-3-743-78, TU 14-3Р-197-2001, TU 14-3-1654-89|
|Blanks. Of the workpiece. Slabs||В31||OST 3-1686-90, TU 14-1-1924-76, TU 14-1-565-84, TU 14-1-790-73, TU 14-3-770-78, TU 14-1-2583-78|
|Castings, non-ferrous metals and alloys||В84||RD 9257-76|
|Thermal and thermochemical treatment of metals||В04||STP 26.260.484-2004|
|Welding and cutting metals. Soldering, riveting||В05||TU 14-1-656-73|
|Bars and shapes||В32||TU 14-11-245-88|
According to GOST 5632-72, the content of Ti% = 5C% is 0.6%.
According to TU 14-3-743-78, the titanium content at the lower limit should be at least 0.30%.
According to TU 14-1-2583-78, the chemical composition is given for steel grade 08H18N12T with a limited content of cobalt and smelted on a fresh charge using highly pure materials and nickel grades NKS-1 and H-0. The mass fraction of titanium in the steel 08X18N12T should be Ti% = 5C% - 0.6%.
|Section, mm||sT|s0,2, MPa||σU, MPa||d5, %||y, %||KCU, kJ/m2|
|Tubes of small dimensions (capillary) heat-treated or cold-worked in the state of delivery according to GOST 14162-79|
|Hot rolled sheet (of 1.5-3.9 mm) and cold rolled (0,7-3,9 mm) steel according to GOST 5582-75. Quenching in water or air from 1050-1080 °C|
|Hot rolled sheet (4,0-50,0 mm) and cold rolled (4,0-5,0 mm) steel according to GOST 7350-77. Quenching in water or air from 1030-1080 °C|
|Bars hot rolled and forged on the other 14-1-656-73. The longitudinal samples. Quenching in water from 1000-1050 °C|
|Bars hot rolled and forged at STP 26.260.484-2004. Quenching in water or air from 1000-1080 °C|
|Seamless hot deformed tubes in the delivery condition according to GOST 9940-81|
|Seamless hot-rolled pipes on the other 14-3-743-78. Austenization at 1040-1060 °C, air cooling or water|
|Seamless tubes with a diameter up to 60 mm cold-worked state beyond 14-3-770-78|
|Tubes seamless cold-and warm of improved quality in the delivery condition on the other 14-3-1109-82|
|Pipe hot rolled, cold rolled and cold drawn. Quenching in water or air with 1060-1080 °C|
Description mechanical marks
|sT|s0,2||Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2%|
|σU||Limit short-term strength|
|d5||Elongation after rupture|
|y||The relative narrowing|
|Temperature||Е, HPa||r, kg/m3||l, W/(m · °C)||R, Mr. · m||С, J/(kg · °C)||a, 10-6 1/°C|
A description of the physical symbols
|Е||The normal elasticity modulus|
|l||Coefficient of thermal conductivity|
|R||UD. the resistivity|
|Weldability||Satisfactory weldability. Welding methods: SMAW electrodes DH-15-1 for the root of the weld, CG-15 for the subsequent layers. CT-26 for those cases where no requirements for resistance to the ICC, CBS and ESW. Recommended subsequent heat treatment. For joints of NPP equipment recommended automatic arc welding under flux.|
|Machinability||Has satisfactory machinability. In the hardened state when HB 170 and blower SB=470 MPa Kn TV.SPL.=0,85 Kn b.St.=0,35.|
|Microstructure||The content of ferritic phase in rods with a diameter or a side of a square of 80 mm or more should not exceed 1.0 points (2,5-3,5 %) Rods with a diameter or side of less than 80 mm and the strip is not subjected to a determination of the ferritic phase.|
|Features of heat treatment||Depending on assignment, working conditions, corrosive environment the product is subjected to: a) hardening (austenization); b) stabilizing annealing; C) annealing for stress relieving; d) a stepwise processing. The product is quenched in order to: a) prevent the tendency to intergranular corrosion (products can operate in temperatures up to 350 °C); b) to increase resistance against General corrosion; C) to eliminate the revealed tendency to intergranular corrosion; g) to prevent the tendency to stab corrosion (welded work product in solutions of nitric acid); d) to eliminate residual stress (products simple configuration); e) to increase the plasticity of the material. The quenching products should be carried out on mode: heating to 1050-1100 °C, items material thickness up to 10 mm cooling on air, more than 10 mm in water. Welded parts of complex configuration in order to avoid the leash is to be cooled in the air. The holding time at the heating for hardening to products with a wall thickness up to 10 mm - 30 min, over 10 mm - 20 min + 1 min per 1 mm maximum thickness. In the hardening of products, intended for operation in nitric acid, the heating temperature for hardening must be kept at the upper limit (exposure at the same weldment should be not less than 1 hour). Stabilizing annealing is applied to: a) prevent the tendency to intergranular corrosion (products work at temperatures above 350 °C); b) stress relief; C) the elimination of discovered tendency to intergranular corrosion, if for any reason hardening is inappropriate. A stabilizing annealing, for example for products and welded joints of steels in which the ratio of titanium to carbon 5 or more of niobium to carbon greater than 8. Stabilizing annealing to prevent the tendency to intergranular corrosion products, operating at temperatures over 350 °C can be subjected to steel containing not more than 0.08 % of carbon. Stabilising annealing should be carried out according to the mode: heating up to 870-900 °C, exposure time of 2-3 h, cooling in air. During heat treatment of large welded products are permitted to carry out local stabilizing annealing of closing seams in the same mode, with all welded components shall be subjected to a stabilizing annealing before welding. In the case of local stabilizing annealing is necessary to ensure both uniform heating and cooling across the length of the weld and adjacent base metal zones for a width equal to two or three widths of a seam, but not more than 200 mm. Manual heating method is invalid. For a more complete removal of residual stresses, the annealing products of stabilized chromium-Nickel steels is performed according to the mode: heating up to 870-900 °C; exposure of 2-3 h, cooling with the furnace to 300 °C (cooling rate of 50-100 °C/h), then by air. The annealing is carried out for products and welded joints of steel, from which the ratio of titanium to carbon 5 or more of niobium to carbon greater than 8. Step processing is to: a) relieve residual stresses and prevent the tendency to intergranular corrosion; b) to prevent the tendency to intergranular corrosion of welded joints of complex configuration with sharp transitions in thickness; C) products with the tendency to intergranular corrosion, remove which other method (annealing or stabilizing annealing) is inappropriate. Step treatment should be carried out according to mode: heating to 1050-1100 °C; the holding time at the heating for hardening to products with a wall thickness up to 10 mm - 30 min, over 10 mm - 20 min + 1 min per 1 mm of maximum thickness; cooling as fast as possible to 870-900°C; holding at 870-900 °C for 2-3 hours; cooling with the furnace to 300 °C (speed of 50-100 °C/h), then by air. To expedite the process, step-by-step treatment is recommended in two in two furnaces heated to different temperatures. When transferring from one furnace to another, the temperature of the products should not be below 900 °C. Speed of processing permitted for products and welded joints of steel, from which the ratio of titanium to carbon 5 or more of niobium to carbon greater than 8.|