August 2023 Volume 5

MAINTENANCE

MATERIALS

performance. Some of them are modifications of hot work type tool steels while others have no relationship to known alloys. • Weld Mold 9580 is a modified H12 tool steel with an as welded deposit hardness of 54-58 Rc. Used in shallow impressions of less than 1 inch or as the capping alloy of a lower hardness layer of weld, 9580 maintains its red hardness resistance to wear up to 1,100⁰F. The hardness of 9580 requires inserted tooling or EDM to re-establish the impression on re-sink. This material cannot be cut with a torch. • Weld Mold 9650 develops an as welded hardness of 44-46

• Weld Mold 958 is an AISI H12 tool steel recognized for its resistance to thermal softening, impact and abrasion. With a hardness of 54 – 58 Rc the utility of this alloy is excellent and is a lower cost alternative to Cobalt based alloys. • Weld Mold 606 is cobalt based Stellite® 6. With a welded

hardness of 40 - 45 Rc this alloy is known for being unaffected by high temperatures but is difficult to weld without developing cracks. 35 Rc, this alloy can work harden up to 45 – 48 Rc. Because this alloy can be machined with relative ease it has become more popular in recent years.

Rc that has proven very versatile as the base layer in a composite die weld repair and as a solo material. The high strength and toughness can be a problem solver in crack prone die cavity designs.

• Weld Mold 621 is cobalt based Stellite ®21 and is the least crack sensitive of the Stellites®. With an as welded hardness of 33 –

• Weld Mold 954 is a proven performer where other alloys have failed but deposits a medium hardness deposit of 38 – 42 Rc with excellent red hardness wear resistance that is machinable with conventional tooling. • Weld Mold 964 is a unique alloy that was developed especially

• Weld Mold 9551 is a new Patent Pending iron based alloy developed to be used on trim tooling. Designed specifically to be a low cost, readily available alternative to the costly and sometimes scarce cobalt based alloys, 9551 offers an as welded

hardness of 42 – 46 Rc. This alloy has been uniquely formulated to achieve an ultimate hardness of 56 – 58 Rc with a combination of work and age hardening.

for use on tooling used to forge aluminum and titanium with an as welded deposit hardness of 50 – 54 Rc. The unique alloying makes conventional machining difficult and EDM or grinding is recommended.

As with most things, forge die welding alloys evolve over time, or new alloys are developed to meet new demands imposed by the industry to provide increases in productivity or other, more specific goals. Weld Mold has spent 78 years on the innovative edge of forge tooling weld repair, expanding on the alloys, process and procedure that originated with Mathew Kiillunen in the first successful flood weld in 1952. David Lee Technical Director Weld Mold Company Email: dlee@weldmold.com Phone: 1-800-521-9755

Because each forging operation is unique, alloy selection alone is not the only consideration that will provide success or failure in a forge tooling weld program. Developing the appropriate suite of equipment, adopting the correct process and consistent adherence to a proven procedure has been shown to be just as important to a program’s success as the alloy choice. In most cases, even when process and equipment are up to snuff, if the procedure is not followed then failure is almost inevitable. Trim Tool Alloys Forge tooling consists of more than just the impression dies, it also includes the trim. This group is also subject to abrasive and high temperature wear, but the character of the work is different and because of this the alloy choices used to maintain them has a different focus. This group of alloys must maintain their shape and condition in a shearing situation. In recent years the following Stellites® have become increasingly costly and can be difficult to get with lead times of several weeks, if not months.

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