T4 High Speed Tool Steel (T4, 1.3255, S 18-1-2-5, SKH3)

• Standard: DIN, JIS, AISI, ASTM, GB, BS
• Technics: Hot Rolled
• Application: Tool Steel Bar
• Surface: Black
• Alloy: Alloy
• Special Use: High-strength Steel Plate, Wear Resistant Steel, Silicon Steel, Cold Heading Steel, Free Cutting Steel, Mold Steel
• Model NO.: T4, 1.3255, S 18-1-2-5, SKH3
• Trademark: Bozhong
• Origin: China
• Production Capacity: 50000tons/Month

Product Description

Products Details

T4 High Speed Tool Steel (T4, 1.3255, S 18-1-2-5, SKH3)

T4 Steel Round Bar: diameter 2mm - 200mm
T4 Steels Flat: thickness 2-20mm x width 10-100mm
T4 Steel Plate: thickness 2-200mm x width 200-810mm
Surface Finish: Black, Rough Machined, Turned or as per given requirements.

2.Relevant Steel Specifications of AISI T4 High Speed Tool Steels

Country	USA	German	Japan
Standard	ASTM A600	DIN EN ISO 4957	JIS G4403
Grades	T4/T12004	S 18-1-2-5/1.3255	SKH3

3.AISI T4 Tool Steel and Equivalents' Chemical Composition

ASTM A600	C	Mn	P	S	Si	Cr	V	W	Mo	Co
T4	0.70	0.80	0.10	0.40	0.03	0.03	0.20	0.40	3.75	4.50	0.80	1.20	17.50	19.00	0.40	1.00	4.25	5.75
DIN ISO 4957	C	Mn	P	S	Si	Cr	V	W	Mo	Co
S 18-1-2-5/1.3255	0.75	0.83	…	0.40	0.03	0.03	…	0.45	3.80	4.50	0.80	1.20	17.50	18.50	0.50	0.80	4.50	5.50
JIS G4403	C	Mn	P	S	Si	Cr	V	W	Mo	Co
SKH3	0.73	0.83	…	0.40	0.03	0.03	…	0.45	3.80	4.50	0.80	1.20	17.00	19.00	…	…	4.50	5.50

4.High Speed Steel T4 Tool Steel Mechanical Properties

• Physical Properties of High Speed T4 Tool Steels

  • Physical properties (average values) at ambient temperature

  • Modulus of elasticity [103 x N/mm2]: 217

  • Density [g/cm3]: 8.70

  • Thermal conductivity [W/m.K]: 19.0

  • Electric resistivity [Ohm mm2/m]: 0.65

  • Specific heat capacity[J/g.K]: 0.46

• Mechanical Properties of T-4 Steel

Properties	Metric	Imperial
Modulus of elasticity	190-210 GPa	27557-30458 ksi
Poisson's ratio	0.27-0.30	0.27-0.30

• Thermal Properties of T4 Tool Steels

Properties	Metric	Imperial
Thermal expansion co-efficient	11.9 µm/m°C	6.6 µin/in°F

 5.Forging of ASTM T4 Tool Steel Materials

Forging of T4 steel can be carried out from 850 to 1120°C (1775 to 2100°F).

• Preheat T4 steel material uniformly and slowly to 860-880°C.

• Increase the forging temperature up to 1050-1120°C.

• T4 hss tool steel should be cooled very slowly after forging.

6.AISI/ASTM T4 Tool Steel Heat Treatment and Properties

• Hardening

Harden T4 high speed tool steel from a temperature of 1260-1290oC followed by oil, air quenching or warm bath at 550oC. Hardness after quenching is 63-66 HRC.

• Annealing

T4 steel should be annealed after hot working. Increase the temperature of T4 high speed steel to 860°C(Max220°C per hour). Hold at the temperature and then cool slowly with the furnace. The annealed hardness achieved should be below HB255.

• Tempering

Tempering temperature: 2x 560-580oC. Hardness after tempering is 64-65 HRC.

7.Applications of ASTM/AISI T4 Tool Steel

AISI T4 high speed tool steels are widely used as cutting tools, broaches and cold extrusion punches, turning, planing and milling cutters for roughing work.

Typical applications are:

• Drills,

• Milling Cutters,

• Thread Cutting Tools,

• Knurling Tools,

• Cold extrusion punches

• Broaches etc.