T4 Steel | AISI T4 | 1.3255 | SKH3

WALDUN is a China top T4 steel manufacturers and suppliers. WALDUN can supply round bar,square bar,flat bar,plate,sheet and wire. T4 Steel is one of tungsten type high speed tool steel according to ASTM/A600 standard. Compared with T1 steel , the composition is very similar,but T4 steel has additional 5% Cobalt which improves the high temperature hardness and red hardness.T4 steel can be hardened with hardness  66-70HRC.

T4 Steel Supply Form & Size & Tolerance

Round bar
Diameter	1-16mm	10-50mm	50-180mm	180-300mm
Process	Cold Drawn	Hot Rolled	Hot Forged	Free Forging
Flat bar
Thickness	1-2.5mm	1.5-20mm	20-300mm
Width	Max 800mm	Max 800mm	Max 800mm
Process	Cold Drawn	Hot Rolled	Hot Forged

Remark:Tolerance can be customized as per requests

T4 Steel Chemical Composition

Standard	Grade	C	Mn	P	S	Si	Cr	V	Mo	W	Co
ASTM A600	T4	0.70-0.80	0.1-0.4	0.03	0.03	0.2-0.4	3.75-4.5	0.8-1.2	0.4-1.0	17.5-19.0	4.25-5.75
DIN EN ISO 4957	1.3255	0.75-0.83	0.4	0.03	0.03	0.45	3.80-4.5	0.8-1.2	0.5-0.8	17.5-18.5	4.50-5.50
JIS G4403	SKH3	0.73-0.83	0.4	0.03	0.03	0.45	3.80-4.5	0.8-1.2	—	17.0-19.0	4.50-5.50

T4 Steel Physical Property

Density, g/cm3	8.68
Melting point,°C	1432
Thermal conductivity, W/m.K	19
Electric resistivity,Ohm mm2/m	0.65
Specific heat capacity,J/g.K	0.46
Thermal expansion co-efficient,µm/m°C	11.9

T4 Steel Mechanical Property

Modulus of elasticity	190-210 GPa
Poisson’s ratio	0.27-0.30

T4 Steel Forging

Pre heat the AISI T4 with two steps.First,heat slowly and uniformly to 860-900°C with a rate not exceeding 220°C per hour,second,heat more quickly to the forging temperature of 1050-1150°C.Re-heating is necessary when temperature below 900°C. Slow cooling in furnace after forging.

T4 Steel Annealing

Annealing must be performed after hot working and before re-hardening.Heat the temperature to 820 to 850°C with a rate not exceeding 220°C per hour.Controlled slow cooling in furnace at 10 to 20°C per hour to approximately 550°C, followed by cooling in still air. Hardness after annealing 265 Brinell, maximum.

T4 Steel Stress Relieving

It is recommended to stress relieve after machining and prior to hardening to minimise the possibility of distortion.Heat in a neutral atmosphere to the  temperature of 600 to 650°C, and  soak for approximately two hours,followed by slow cooling in the furnace.

T4 Steel Hardening

Preheat AISI T4 steel slowly to the temperature of 820-870°C,then heat T4  uniformly to  the  temperature 1260-1290^oC ,followed by oil, air quenching or warm bath at 550^oC.

T4 Steel Tempering

Tempering should be carried out immediately after quenching. Heat slowly and uniformly to the tempering temperature 560-580^oC,soak well not less than 2 hours(one hour per 25mm of total thickness).Double tempering is recommended,hardness after tempering is 64-65 HRC.

T4 Steel Application

AISI T4 high speed steel is widely used to make various cutting tools of higher temperature.

Typical use include:turning tool,cutter,reamer,forming cutting tools,drilling tools,broaches and cold extrusion punches, planing and milling cutters for roughing work.