18HGT

CARBURISING STRUCTURAL STEEL

NORM: PN-89/H-84030/02

APPLICATION:

Steel susceptible to loaded parts with a high core strength. Especially for gear wheels and shafts.

TECHNOLOGICAL INFORMATION:

The steel can be welded before carburising, but after pre-heating.

SEMI-FINISHED PRODUCTS:

The steel can be welded before carburising, but after pre-heating.

MECHANICAL PROPERTIES:

Property	Symbol	Unit	Value
Ultimate tensile strength	Rm	MPa	≥ 980
Yield stress	Re (Rp0.2)	MPa	≥ 830
Elongation	A	%	≥ 9
Reduction of area	Z	%	≥ 50
Impact energy	KV	J	≥ 80
Hardness after soft annealing	–	HB	≤ 217

Technological treatment processes:

Technological treatment processes			Possible application	Temperature, °C
Hot forming	Forging		+	1100 – 850
	Rolling		+	1100 – 850
Thermochemical treatment	Carburising		+	880 – 950
	Carbonitriding		+	860 – 930
Heat treatment	Annealing	Normalising	+	880 – 900
		Soft annealing	+	650 – 700
	Heat treatment after carburising1)	Core hardening	+	850 – 880
		Intermediate annealing	+	660 – 680
		Case hardening	+	810 – 830
		Tempering	+	150 – 200
1) If possible, hardening has to be performed with the temperature equal or close to the heat treatment temperature

INTERNATIONAL STEEL GRADES: