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R18 steel

P18 steel

Steel P18: Handbook of steels and alloys. Below is systematized information on the purpose, chemical composition, types of supply, substitutes, critical point temperatures, physical, mechanical, technological and foundry properties for the grade — Steel P18.

General information on steel R18

Substitute for the brand
steel R12.
Kind of delivery
Rails Р18, circle Р18, strip Р18, square Р18, section rolled steel, including shaped: GOST 19265−73, GOST 2590−71, GOST 2591−71. Calibrated bar GOST 19265−73, GOST 7417−75. Grinded rod and silver GOST 19265−73, GOST 14955−77. Thick plate TU 14−1-1408−75. Sheet thin TU 14−1-1408−75, TU 14−1-1706−76. GOST 19265−73, GOST 4405−75. Wire TU. 14−1-1096−74. Forgings and forged blanks GOST 19265−73, GOST 1133−71.
Application
Chisels, drills, milling cutters, thread cutters, chisels, reamers, countersinks, taps, broaches for machining constructional steels with the strength to 1000 MPa, which require keeping the cutting properties when heated during operation up to 600 ° C.

Chemical composition of steel R18

Chemical element %
Vanadium (V) 1.00−1.40
Tungsten (W) 17.0−18.5
Cobalt (Co), not more than 0.50
Silicon (Si), not more than 0.50
Manganese (Mn), not more than 0.50
Molybdenum (Mo), not more than 1.00
Nickel (Ni), not more than 0.40
Sulfur (S), not more than 0.03
Carbon (C) 0.73−0.83
Phosphorus (P), max. 0.03
Chrome (Cr) 3.80−4.40

Mechanical properties of R18 steel

Mechanical properties depending on tempering temperature

t tempering temperature, °C σB, MPa KCU, J/m2 HRCe
Quenching at 1280 °C, oil. Tempering three times for 1 h.
400 1370 23 61
500 1470 19 63
550 2350 17 66
600 2210   65

Technological properties of R18 steel

Forging temperature
Beginning 1200, ending 900. Cooling in the wells at 750−800 C.
Weldability
The weldability is good when electrically joined with steel 45 and 40X.
Grindability
excellent (GOST 19265−73).

The temperature of critical points of steel R18

Critical point °С
Ac1 820
Ac3 860
Ar3 770
Ar1 725

Physical properties of steel R18

Test temperature,°C 20 100 200 300 400 500 600 700 800 900
Modulus of normal elasticity, E, GPa 228 223 219 210 201 192 181      
Torsional shear modulus of elasticity G, GPa 83                  
Steel density, pn, kg/m3 8800                  
Thermal conductivity coefficient W/(m — °C)   26 27 28 29 28 27 27    
Electrical resistivity (p, nominal value — m) 419 472 544 627 718 815 922 1037 1152 1173

Heat resistance, red resistance of steel R18

Heat resistance

Temperature, °C Time, h Hardness, HRCe
620 4 59