Name: H12 Steel
SKU: MSC-H12-T20812

H12 Steel

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Product Overview

H12 is a chromium-molybdenum-tungsten hot-work tool steel designated under AISI and specified in ASTM A681 as UNS T20812. It is a general-purpose hot-work grade containing approximately 5 % chromium with additions of molybdenum, tungsten and vanadium, used for dies and tools requiring toughness and resistance to heat checking.

Similar Designations

Country / Region	System / Standard / Manufacturer	Designation	Designation Type	Relationship	Applicable Scope	Source
Europe / Germany	EN ISO 4957	X35CrWMoV5	National Standard Grade	Similar	Hot-work tool steel chemistry closely matching	[S2]
Europe / Germany	DIN	1.2605	Material Number	Similar	Hot-work tool steel chemistry closely matching	[S2]
Japan	JIS G4404	SKD62	National Standard Grade	Similar	Hot-work tool steel	[S2]
UK	BS 4659	BH12	National Standard Grade	Similar	Hot-work tool steel	[S2]
China	Commercial / GB-related	4Cr5WMoSiV	Commercial Alias	Similar	Catalog slug alignment	[S4]
China	Commercial / GB-related	4Cr5W2VSi	Commercial Alias	Similar	Catalog slug alignment	[S4]

Product Specifications

Parameter	Value	Unit
Max annealed hardness	229	HBW

Standards & Designations

Country / Region	System / Standard / Manufacturer	Designation	Designation Type	Relationship	Applicable Scope	Source
USA	AISI / ASTM A681	H12	Primary Grade	Confirmed	Hot-work tool steel	[S1]
USA	UNS	T20812	Material Number	Confirmed	Same as H12 under ASTM A681	[S1]
Europe / Germany	EN ISO 4957	X35CrWMoV5	National Standard Grade	Similar	Hot-work tool steel chemistry closely matching	[S2]
Europe / Germany	DIN	1.2605	Material Number	Similar	Hot-work tool steel chemistry closely matching	[S2]
Japan	JIS G4404	SKD62	National Standard Grade	Similar	Hot-work tool steel	[S2]
UK	BS 4659	BH12	National Standard Grade	Similar	Hot-work tool steel	[S2]
China	Commercial	4Cr5WMoSiV	Commercial Alias	Similar	Catalog slug alignment; composition ranges approximate H12	[S4]
China	GB-related	4Cr5W2VSi	Manufacturer Grade	Similar	Catalog slug alignment; composition ranges approximate H12	[S4]

Chemical Composition

ASTM A681-08 (2015) H12

C	Si	Mn	Cr	V	W	Mo	P	S	Ni + Cu
0.30–0.40%	0.80–1.25%	0.20–0.60%	4.75–5.50%	0.20–0.50%	1.00–1.70%	1.25–1.75%	≤0.030%	≤0.030%	≤0.75%

Heat Treatment

Manufacturer recommendations for H12 hot-work tool steel processing:

Parameter	Value / Range	Condition / Details	Source
Soft Annealing	845–900 °C	Furnace cool to 540 °C at 10–20 °C/h; hardness ≤229 HB	[S2]
Austenitizing	1010–1050 °C	Quench in oil or air	[S2]
Tempering	520–700 °C	Hold ≥2 h, double temper, air cool	[S2]

Heat-Treatment Graphs

Illustrative only

Technical graphs

For illustration only — do not use as design, acceptance, or guaranteed product data. This graph shows a representative engineering trend, not measured product data. Actual values may vary with material condition, heat-treatment parameters, section size, and production route. Contact MSC for product-specific technical data.

Hardenability

Illustrative only

Technical graphs

For illustration only — do not use as design, acceptance, or guaranteed product data. The curve shown is a representative hardenability trend for this material grade. Actual values may vary depending on heat-treatment parameters, austenitizing temperature, grain size, section size, and steelmaking practice. Contact MSC for product-specific technical data.

Manufacturing & Supply

Attribute	Details
Manufacturing Method	Wrought hot-work tool steel [S2]
Available Forms	Bar, flat, and plate (commercial ranges reported by suppliers) [S2]

Key Features & Advantages

Feature	Explanation
Chromium Content	Contains approximately 5% chromium to provide a balance of hardenability and heat resistance [S1, S2].
Alloy Additions	Alloyed with molybdenum, tungsten, and vanadium for enhanced high-temperature strength [S1, S2].
Crack Resistance	Engineered to offer resistance to cracking and heat checking under severe hot-work conditions [S2].

Applications

Application	Description
Hot Punches	Used for hot punching operations requiring resistance to cracking [S2].
Die-Casting Dies	Applied in die-casting tooling applications [S2].
Extrusion Tooling	Suitable for extrusion dies and press dies [S2].
Hot Shear Blades	Utilized for hot shear blades and hot gripper dies [S2].

Important Notes

Exact product form, dimensional ranges, and delivery condition are not verified for this specific catalog entry. EN ISO 4957 X35CrWMoV5 chemistry is close but not identical and must be kept separate. Heat-treatment data reflect manufacturer recommendations rather than mandatory standard delivery conditions.

Contact / Quotation

For quotations, available forms, dimensions and order-specific technical confirmation, contact MSC.

Hot-Work Tool Steel