Is it tough enough for you?
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Can a new tool steel
that machines like butter really be tough enough to withstand the
pounding that a Tier One automotive stamping plant will put it
through? We ask an "old D-2 boy" what he thinks.
By Chris Cummings, 2001 issue of
Canadian Machinery and
toolmakers, Marty Puncheon of Ajax Precision Manufacturing Ltd. in
Toronto, is a skeptical man. As the toolroom supervisor of this Tier
One automotive parts supplier, he's been around the block and knows
his tooling business as well as anybody. He is a self-confessed "old
D-2 boy," loyal to the tool steel that is considered the industry
standard. So when asked to check out a new kind of tool steel said to
be easier to machine--and yet provides a longer tool life than
conventional tool steels--he was, naturally, skeptical.
But Puncheon ensured Ajax was the first
Canadian plant to try
DC53 tool steel in production. He says he was as surprised
as anybody to find it significantly outperforms alloy tool steel
D-2--long the standard in the industry--in the applications in which
he has tested it.
Because of the steel's ability to
withstand compression and shock, this Toronto stamping plant reports
it is getting 10 times more hits, double to triple the tool life, 30%
less machining time, much faster grinding time and 30% less downtime
when used in its progressive dies.
REDUCES CRACKING AND CHIPPING
The steel sharply reduces cracking and
chipping and the number of processes involved in the stamping
industry, and provides better hardness after heat treatment. Moreover,
unlike competing die steels, it is inexpensive, costing between D-2
and the powdered metal steels.
The plant, one of three operated by
Ajax Precision Manufacturing Ltd., mainly makes automotive parts for
the Big Three car companies. A Tier One supplier to General Motors,
Ajax is currently making almost 70 parts for the new smaller version
of the Hummer vehicle manufactured by GM in the United States. For
more than 20 years, Ajax has also made brake shoes for rail cars. The
plant has 32 presses and 24 robotic and spot welders; it employs 205
DC53 is particularly effective in
applications where long-lasting tool steel able to take shock and not
crack is called for. Although Ajax has so far used it in several
applications, including cutting, DC53 is a general all-purpose tool
steel that can be used in forming and coining operations as well. The
steel is now being used in about 20 other manufacturing plants and
shops in Canada.
Puncheon was skeptical about DC53 when
Titus Steel of Mississauga, Ont., offered it to him several months
ago. It had no track record in Canada and he doubted anything could
outperform familiar tool steels such as D-2, which has been the
industry standard for decades.
"I was hesitant to try something new.
I'm an old D-2 boy and I'd never found anything else around. I didn't
believe it would do what they claimed it would. I was given some
sample DC53 to try out. At first, I was reluctant to say it was any
good because I watched how easily it machined; it cut like butter. I
said any steel that machines that easily couldn't be any good. But we
finished the part, had it heat-treated and installed it in the die. I
had egg on my face because it worked. I couldn't believe it. In my 30
years in the business, I've never seen a steel do what it did."
Chris Martin of Titus Steel points out
several more advantages of DC53 compared to other tool steels. The
material has less residual stress after EDM wire cutting. You can heat
it to 63 HRC without losing its toughness and without it becoming
brittle. You don't have to pre-heat treat or post-harden DC53 when
coating using CVD (chemical vapour deposition) or TD (thermal
diffusion). DC53 does not "move" as much as other tool steels during
these hot coating processes. So you don't lose as much hardness. And
you can save money on your heat-treating and post-hardening processes.
Welding and general repair is much easier with DC-53 than with other
100,000 HITS VS. 10,000 HITS
Puncheon notes that, in one particular
application with D-2, he gets 10,000 hits on the stamping press. Both
DC53 and Vanadis 4 give him more than 100,000 hits but DC53 costs
"And it's not just the ease and speed
of machining I like: It cuts down on maintenance; you're not wearing
out as many cutters and it gives longer life to grinding wheels."
DC53's molecular construction is what
makes it perform efficiently. Its carbides are one-third smaller and
more rounded and uniform than D-2's. Because D-2's carbides are bigger
and more angular, kick-back is more likely to occur when machining or
"With D-2, your grinding wheel will
wear down faster because of the sharp carbides in the steel," Pucheon
says. "You get heat when you start grinding on a taper. DC53 does not
destroy the wheel as fast; you still have that leading edge which
gives you a narrower cutting face, and, obviously, less heat. So it's
much better grinding. It's also easier on the cutters when you machine
it; you're not breaking up cutters or making the cutters dull."
CAN BE HARDENED UP TO 63 HRC
DC-53, made by Daido of Japan, can be
hardened up to 63 HRC without losing its toughness or becoming
Puncheon was particularly impressed by
how the steel worked on one "nasty" 18-year-old die that has always
been awkward to work with.
"The die takes a lot of pressure: It
draws about 470 tons. One small round station about 3-in. diameter
takes about 400 of those tons. I hadn't found a steel that would stand
up to it. I'd used D-2, Vanadis 4, H13, S7. I've tried them all and
nothing worked. The best was Vanadis 4; I got about 100,000 hits with
it but I had to stress-relieve it all the time. It's hard to grind or
machine because it's a very tough material. DC53 did the job," but it
does also need some stress relieving, he adds.
The steel has helped Puncheon overcome
other problems. "I have a couple of dies with developed holes. The
sidewalls are extruded but it's an irregular shape. The two dies are
the same: If they get a little dull where the flanges are extruded,
the part rips and I get rejects from the customer. Before getting
DC53, I had to sharpen the dies every two runs maximum with D-2
punches and die-sections. So I put the DC53 in and one die has been in
and out of the press eight times and it's still running. The parts
aren't cracking; it's holding its edge. It's giving me a better cut.
"I don't build dies, I repair them. I
have presses of up to 600 tons. The number one consideration for me is
that they have to run. When I have a breakdown it has to be repaired
fast due to the customer's needs and press scheduling. Equally
important is the quality of service; it means more than cost. The
supplier who can get the steel to me in an hour, even though he's more
expensive, is better than the supplier who takes two days."
EXPERIMENTING WITH COATINGS
He hasn't yet tried the tool steel with
protective coatings, but plans to. "If I see a die design that looks
problematic, I'll try it (a protective coating). I'd try DC53 in
almost any application in the stamping industry. I will experiment
with coatings. I have some dies that require a difficult draw. It
doesn't matter what steel I use, the die requires a special coating on
it. D-2 moves after being reheat-treated after coating. I can save
money on the heat-treating cycle with DC53." The steel can be coated
with PVD, CVD (chemical vapour deposition), TD and other coatings,
extending tooling life.
Ajax, a recently incorporated company,
has other plants besides the stamping plant, the firm's original site.
It has a plant nearby in Mississauga and a new 100,000-ft2 corporate
head office and stamping facility in Brampton, northwest of Toronto.
Ajax was started in a Toronto basement in the 1930s, manufacturing
compact cases and drafting equipment. During World War II, it made
munitions for the war effort, and, afterward, began stamping
automotive parts. The current owner, Bruce Mitchell, acquired the
company in 1976. The steadily growing company employs more than 500
Chris Cummings is a regular
contributor to Canadian Machinery and Metalworking.