Brad Kuvin Brad Kuvin
Editorial Director

New Die Steel Reduces Wear on Form Details

February 27, 2023

Stamping locking mechanisms for automotive applications—locks on doors, trunk lids, tailgates and the like—can punish tooling, in particular form tools, as these mechanisms commonly are stamped from Type 4130 Cr-Mo steel. These steels, heat-treat hardened, have a 670-MPa yield strength and a 92 Rockwell B hardness, ideal properties when machining drill bits and taps or for fabricating rock-crushing machinery. But try to form them in stamping presses and the form steels can become susceptible to premature wear.

striker base plateSuch has been the case at locking-mechanism manufacturer Gecom Corp., Greensburg, IN, which operates a variety of presses from 80-ton single-hit presses performing secondary operations, to 600-ton progressive-die presses. The 400,000-sq.-ft. Gecom facility employs nearly 500 people to supply several major OEMs consistently and reliably. To help ensure that premature die wear doesn’t negatively affect its ability to remain a preferred supplier, the firm recently upgraded its tool steel of choice for select form details to prolong life between sharpenings, and to reduce the amount of sharpening needed during tool maintenance. So says assistant tool and die engineering manager Jackie Bishop.

Diehl-Tool-Steel-tool“We’re consistently innovating and trialing new tool-material types,” Bishop shares, “rather than locking into a routine of constant repair and maintenance, which our toolroom found itself in when relying solely on D2 or DC53 tool-steel grades. We recently saw an opportunity to trial new die steels that not only have improved production-hit counts, but also decreased the maintenance and replacement times within the toolroom. We’ve enjoyed a lot of cost savings on the maintenance and repair side as a result, and any premium we’ve paid for the new form details has resulted in better profitability and better workflow within the toolroom and plant. The added investment has been easily justified.”

The Push for Maintenance-Friendly Tooling

Efforts to make its tools more “maintenance-friendly,” says team leader Scott Davidson, led the firm, late in 2021, to trial form tools fabricated from two matrix-grade high-speed steel alloys—YXR7 and YXR33, exclusively distributed by Diehl Tool Steel, a Proterial Group company. Both grades, say Diehl representatives, prove ideal in tooling that requires high impact toughness and resistance to chipping. 

After plenty of trial runs begun late in 2021 (using an aluminum-chromium-nitride tool coating), Gecom has found that YXR7 (0.8 C, 4.7 Cr, 1.3 W, 5.5 Mo, 1.3 V) performs best in trimming and forming applications. The firm has used the alloy for six trim punches and six forms, and on several additional small details.

“Our form details machined from D2 and DC53 tend to wash out pretty quickly,” says Davidson, “sometimes after only 50,000 hits, and then require resharpening. With the matrix-grade tool steels, not only do we get 200,000 hits or more between sharpenings, but each sharpening only requires our machinists to remove 0.010 in. or so of material, a dramatic improvement from the need to remove as much as 0.2 in. of D2 material for sharpening.”

Blanking Tools Require a Tougher Grade

For jobs requiring optimum toughness—progressive-blanking tools—Gecom trialed YXR33 (0.5 C, 4.2 Cr, 1.6 W, 2.0 Mo, 1.2 V). The performance has been stellar, the Gecom team reports, “outperforming a previously used powdered-metal tool steel by more than four to one,” says Gecom journeyman tool and die maker Kyle Land. “We’ve made well over 400,000 hits so far with that tool since the change without resurfacing. The tool holds three punches to blank out three parts per stroke.”

“We’ve been trialing the new steels for just over a year,” Davidson adds, “and the greatly improved performance has led to placing additional work orders with Diehl Tool Steel to try the matrix grades on other die details. The program has been a big hit so far, so we’re prioritizing the applications that we want to work on next.”

When the conversation turns to cost-justification, “the return on investment is a no-brainer,” Davidson insists. “The grades are more expensive than D2 but not as pricey as S7; however, we used to sharpen the D2 details weekly, and the deeper cuts when sharpening added up to 16 hr. of weekly tool maintenance. With the new matrix-steel tools, we’re running 4 weeks between sharpenings and only 8 hr. needed per sharpening. At the end of the day, we’ve reduced tool-maintenance time by more than 56 hr./mo.”

More Out-of-the-Box Thinking

The team at Gecom, a subsidiary of Japan-based Mitsui Kinzoku ACT, sees the tool-steel investigation as just another continuous-improvement project among many performed in recent years.

“With the economy the way it is and labor tight,” says Bishop, “we’ve been tasking our engineering department to find ways to make all of our operations more efficient and productive.”

This mindset is evident throughout the company's activities ranging from completing research, design and inhouse fabrication of an autonomous scanning door-striker inspection cell to working with partners to develop wire forming robotic cells.

“The drive toward innovation and lower costs has led to an impressive revamp of our tooling department,” Bishop says, noting that the toolroom runs two Haas machining centers (with one operator managing and programming both) as well as four conventional mills, two CNC lathes and an EDM room with two sinker machines and four wire machines. 

“We have always performed 99 percent of our tooling maintenance inhouse, but now we can operate as a job shop providing assembly and engineering as well.” he adds. MF

Industry-Related Terms: Blank, Case, CNC, Die, Form, Forming
View Glossary of Metalforming Terms


See also: Diehl Tool Steel Inc.

Technologies: Tooling


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