Special Steel Flat Bar Specification

• Customization: Available
• Type: Special Steel Bar
• Standard: AISI, ASTM, DIN, JIS, GB, BS
• Model NO.: round bar
• Composition: Stainless Steel Scrap
• Technique: Forged
• Shape: Bar
• Surface Treatment: Polished
• Special Use: High-strength Steel Plate, Wear Resistant Steel, Free Cutting Steel, Mold Steel
• Application: Die Steel Bar
• Transport Package: Wooden
• Specification: 6-400mm
• Trademark: Smooth
• Origin: China
• HS Code: 7214100000
• Production Capacity: 5000

Product Description

1.2379/D2/SKD11

Brief Description
D2 Tool SteelD2 Tool Steel is a versatile, high-carbon, high-chromium, air-hardening tool steel. It is known for its high attainable hardness and the presence of numerous, large, chromium-rich alloy carbides in its microstructure, which provide excellent resistance to wear from sliding contact with other metals and abrasive materials. While there are other steels with improved toughness or wear resistance, D2 offers a balanced combination of wear resistance, toughness, tool performance, price, and a wide variety of product forms. The remelting process enhances its chemical homogeneity, refines carbide size, and improves mechanical and fatigue properties.
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1. Size Range for D2 Tool Steel
D2 Steel Round Bar: Diameter 80mm~330mm
D2 Steel Plate: Thickness 25mm~400mm x Width 200mm~800mm
Delivery Condition:
Turned Round Bar, Milling Plate, Black, and available per customer requirements.
Spheroidizing Annealing, ESR material.
2. D2 Tool Steel Equivalent Grades

Country	USA	German		Japan	China
Standard	ASTM A681	W-nr.	DIN	JISG4404	GB/T1299-2000
Grades	D2	1.2379	X155CrVMo121	SKD11	Cr12Mo1V1

3. D2 Tool Steel Chemical Composition

Grades	C%	Si%	Mn%	P%	S%	Cr%	Mo%	V%
D2	1.40~1.60	0.30~0.50	0.30~0.50	≤0.03	≤0.03	11.0~13. 0	0.70~1.20	0.80~1.10
1.2379/X155CrVMo121	1.50~1.60	0.10~0.40	0.15~0.45	≤0.03	≤0.03	11.0~12.0	0.60~0.80	0.90~1.10
SKD11	1.40~1.60	≤0.40	≤0.60	≤0.030	≤0.030	11.0~13. 0	0.80~1.20	0.20~0.50

4. D2 Tool Steel Physical Properties
The physical properties of D2 Tool Steel are listed in the tables below. The elastic modulus is 207,000 MPa, and the specific heat at constant pressure (Cp) is 461 J/(kg·K).
Critical Temperature of D2 Tool Steel

Critical point	Ac1	Acm	Arcm	Ar1	Ms
Temp.(approximation)	1490°F (810°C)	1607°F (875°C)	1382°F (750°C)	1283°F (695°C)	374°F (190°C)

Coefficient of Linear Thermal Expansion

Temperature	68~212°F (20~100°C)	68~392°F (20~200°C)	68~572°F (20~300°C)	68~752°F (20~400°C)
Coefficient	10.5 x10^-6	11.5 x10^-6	11.9 x10^-6	12.2 x10^-6

5. Forging of D2 Tool Steel

Items	Heating temperature	Starting forging temperature	Final forging temperature	Cooling
Ingot	2048~2120°F (1120~1160°C)	1922~1994°F (1050~1090°C)	≥1562°F(850°C)	Hot charging annealing
billet	2048~2084°F (1120~1140°C)	1922~1958°F (1050~1070°C)	≥1562°F(850°C)	Hot charging annealing,cooling in hole or dust

6. Heat Treatment
Soft Annealing
Protect the steel and heat through to 1560°F (850°C). Then cool in the furnace at 20°F (10°C) per hour to 1200°F (650°C), then freely in air.
Stress Relieving
After rough machining, the tool should be heated through to 1200°F (650°C), with a holding time of 2 hours. Cool slowly to 930°F (500°C), then freely in air.
Hardening
Preheating Temperature: 1110-1290°F (650-750°C). Austenitizing Temperature: 1810-1920°F (990-1050°C), typically 1830-1905°F (1000-1040°C).

Temperature		Soaking time (min)	Hardness before tempering
°F	°C
1815	990	60	approx. 63 HRC
1850	1010	45	approx. 64 HRC
1885	1030	30	approx. 65 HRC

*Soaking time = Time at hardening temperature after the tool is fully heated through.
Protect the part against decarburization and oxidation during hardening.
Quenching
Quench in air or pressurized gas to 150-125°F (66-51°C). Sizes up to 4 inches (101.6 mm) in thickness will through harden when air-cooled from 1575°F (857°C). Sizes up to 6 inches (152.4 mm) in thickness will through harden when air-cooled from 1625°F (885°C).
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Tempering
Temper immediately after quenching. Hold at temperature for 1 hour per inch (25.4 mm) of thickness, with a minimum of 2 hours. Then air cool to ambient temperature. The typical tempering range is 350-400°F (177-204°C).
To achieve maximum wear resistance, temper our Special Steel Flat Bar between 300-350°F (149-177°C) to attain a superior hardness of 62-64 HRC. For an impeccable balance of wear resistance and toughness, temper between 500-550°F (260-288°C), resulting in a hardness of 58-60 HRC. Experience unparalleled performance with these precise specifications.
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For ultimate toughness, apply a double tempering process—2 hours plus an additional 2 hours—at temperatures exceeding 950°F (510°C). This meticulous treatment will yield a hardness of less than 58 HRC, ensuring remarkable durability and resilience.
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7. D2 Tool Steel Applications
D2 Tool Steel is indispensable in a myriad of industrial applications, including blanking, forming, and trim dies; gages; slitting cutters; wear parts; lamination dies; thread rolling dies; drawing dies; rotary cutting dies; knurls; bending dies; gages; shear blades; burnishing tools; rolls; machine parts; master parts; injection screw and tip components; seaming rolls; extrusion dies; tire shredders; and scrap choppers. Its versatility makes it the material of choice for high-performance tools and components.

With over a decade of expertise in producing D2 Tool Steel, Huangshi Smooth Industry and Trade Co., Ltd proudly delivers the highest quality standards. Our D2 Tool Steel products are exclusively ESR (Electro-Slag Remelted) to ensure superior performance and reliability. As our best-selling product, D2 Tool Steel represents our commitment to excellence. If you have any inquiries, please don't hesitate to contact us. We are dedicated to providing the best support and solutions to meet your needs.