Hot-work tool steels must keep useful strength and resist surface damage while the tool cycles through heat, pressure and cooling. A grade name or AISI equivalent is only a starting point: steelmaker products can differ in chemistry, cleanliness, heat treatment and the property balance they are designed to provide. This table keeps the comparison tied to selected Uddeholm products for die-casting applications.

Hot Work Tool Steel Grades and Properties

Read the hardness in its supplied condition

The Brinell values in the table are Uddeholm’s approximate supplied hardness for the listed product grades. They are not recommended working hardness, finished die hardness or a direct measure of service life. Heat treatment changes hardness and can change strength, toughness and dimensional stability. Compare a product’s heat-treatment instructions with the die design and the supplier’s recommended hardened condition before selecting a grade.

For Orvar Supreme, the manufacturer identifies the product with AISI H13 / 1.2344 and describes it as an all-round hot-work grade. Vidar Superior is identified as modified H11 / 1.2340. Dievar, Unimax and QRO 90 Supreme have no AISI equivalent printed in this product comparison. Do not assign an equivalent by guessing from similar chemistry.

Use the chemistry as an identity check

The listed composition values are the manufacturer’s nominal product analysis in weight percent. They help distinguish these product grades; they are not acceptance limits for a heat analysis or a substitute for the purchase specification. The table omits elements the source does not report in its compact comparison, so an omitted element should not be read as zero. For certified composition, use the material test report for the supplied heat and condition.

Composition alone does not determine a die’s performance. Processing route, cleanliness, section size, heat treatment, surface treatment, insert geometry, cooling channels and operating cycle also matter. The product names in the table are manufacturer trade names, not generic grades. When a drawing requires H13, for example, verify whether a named premium product and its applicable specification satisfy the drawing instead of treating every product bearing an H13 association as interchangeable.

Compare the property ratings carefully

Uddeholm’s die-casting brochure also provides qualitative property comparisons for its listed hot-work grades. Those graphics compare properties such as hot strength, ductility, toughness, hardenability and resistance to die failures. The bars are relative rankings within that manufacturer’s comparison, not measured percentages or universal performance scores. The testing condition is important: the source says the compared steels were tested at 44–46 HRC, except Unimax at 54–56 HRC. A rating drawn under those conditions must not be carried over to another hardness or application.

Use the property balance to form a shortlist. A hot-work grade chosen for resistance to heat checking may not be the best option when gross cracking, erosion, plastic deformation or machinability controls the design. Ask the steel supplier which grade and heat-treatment route match the die’s failure mode, section size, surface treatment and production cycle.

Specification and verification

Record the exact trade name, applicable standard or designation, supplied condition, heat-treatment target, hardness measurement method and acceptance range on the purchase documents. Confirm the current technical data sheet and availability with the steel supplier. Check the certification for the actual heat before machining or releasing a tool. This comparison is a screening reference; it is not a material approval or a guarantee of tool life.

Sources

Composition, supplied hardness and qualitative property comparisons are summarized from Uddeholm’s Tool Steel for Die Casting technical brochure. Orvar Supreme’s AISI H13 / 1.2344 designation and manufacturer description are also available on the Uddeholm Orvar Supreme product page. The values are product-specific and should be checked against the current product data sheet.