This technical information has been contributed by
Caterpillar Industrial Products, Inc.

Heat Treatment Services

For years, Caterpillar's products have set industry standards for durability, strength, and technological superiority. Its 1998 sales volume of $20 billion put it in Fortune Magazine's Top 50 and lends substance to Caterpillar's claim to be the world's largest manufacturer of earthmoving, construction, and materials handling equipment-also a major force in the diesel and natural-gas engines market and gas turbine industries.

Last year, Caterpillar manufactured over $300 million of steel gears for its own use and, for decades, has been heat treating gears to meet the tough applications of large, heavy duty construction equipment.

This enviable sales volume has enabled Caterpillar to spend over $40 million putting together world-class heat treating facilities at its Peoria, IL and Joliet, IL plants. Virtually all of Caterpillar's heat treatment equipment is custom made by manufacturers such as Holcroft, Electric Furnace, Surface Combustion, and American Induction. Caterpillar's atmosphere equipment is endothermic-based, and most of the equipment uses natural gas heating.

During the years, it has amassed engineering and production expertise to make gears of exceptional quality and strength. The company's heat treat technology, experience, and capability has played an integral role in maintaining Caterpillar's high quality standards.

Going Commercial

It was not surprising to hear that, after touring the heat treat shop at the Peoria facility, one commercial heat treater commented, "When heat treaters die, this is what their heaven looks like!" These modern facilities provide state-of-the-art, high-tech heat treatment equipment and technology for Caterpillar's needs around the world. Now, in addition to heat treating thousands of part numbers for internal requirements, the company is making its heat treating capabilities available to other companies.

Processing Capabilities

The wide variety of heat treatment processes available include through-hardening, carburizing (batch and press quench), gas nitriding, induction hardening, tempering, straightening, and shot-peening services. Gas nitriding is performed for parts as large as 40 x 54 x 60 in. and conventional hardening and tempering for parts up to 1,100 lb and 36 x 36 X 24 in. Gears as large as 39 in. diameter can be precisely carburized and die (fixture) quenched. Induction heat treat, with frequencies from 3,500 Hz to radio frequencies (RF), is available for shafts or gears to 42 in. diam. and 56-in. long.

Caterpillar factories were designed to produce medium- to high-volume quantities. However, there is a significant amount of flexibility with commercial heat treat orders as small as $ 1,000 being accepted. Heat treatment is available for parts weighing up to 1,000 lb, and down to just a few ounces. For example, two 38in. diameter transfer gears weighing 870 lb each were recently carburized and die quenched. At the other end of the spectrum, small, powder-metal oil pump gears in batches of 1,200 pieces and schedules of 6,000, are routinely carbonitrided.

Technical Support

Extensive engineering and metallurgical staffs support the heat treat facility. Caterpillar analyzes customer needs and offers advice on how to obtain the optimum heat treat process. Benefits include:

The company has experience in performing heat treatment services for other companies. A major OEM approached Caterpillar requesting emergency assistance, because one of the OEM's furnaces had unexpectedly failed. Within 48 hours, Caterpillar was heat treating parts for the OEM.

Fast turnaround time continues to be of paramount importance. When iron from an OEM is received on the dock, the time required for heat treating is as little as three work days. Depending on the type of heat treat required, a maximum of seven work days is required to turn the order around and have it finished and ready to ship back to the OEM.

Checking Up On Quality

The company has a comprehensive, in-depth metallurgical and traceability program to assure quality. Caterpillar uses its own internal certification program (comparable to ISO) to monitor quality and assure all systems are working properly. Its new heat treatment equipment was designed and specified to monitor and adjust critical processing parameters, while maintaining outgoing part quality to that originally tested.

For example, in carburizing applications, atmosphere is controlled by a Caterpillar-developed infrared supervisory system and oxygen probe control. Quality is verified by test pieces with each heat (grid) of material. Test pieces are correlated to part quality by initial setup destructive analysis of the part and audit program for each furnace.

Nitride quality is checked by testing pieces for each heat of material processed and checking the hardness of each part number within a heat. The nitriding process uses automatic controls to assure proper cycling.

AU hardness testers are checked daily and calibrated by an outside lab service. Thermocouples are checked at least monthly to NIST standards (this is an important area that some heat treaters may fail to monitor). Furnaces are surveyed to verify temperature ranges, and the latest in automatic atmospheric controllers guarantees carbon gradients and surface microstructure.

The quality process begins with a test lot or initial production-run iron. Parts are dimensionally checked and destructively analyzed to determine conformance with print requirements. Results are then correlated to standard test coupons run with the parts, and machine parameters under which the parts were processed. This information is collated in a part history folder and is used to generate the part recipe for heat treat that all subsequent heat treatment schedules follow.

On production runs, the same standard test coupons are run with each heat of material and destructively inspected to cross check the automatic systems to guarantee processing identical to initial test parts. The ongoing audit program includes:

Trained Staff

The heat treating staff consists of over 100 operators and management team members. There are a number of degreed Metallurgical Engineers, many of whom hold advanced degrees. Operators average 20 years experience; each has a written job description to guide his/her efforts.

This exceptional work force is necessary due to Caterpillar's high-tech heat treat design approach, which demands a well-managed and operated system with qualified personnel. This is in contrast to some smaller heat treaters, which may have only one or two knowledgeable people directing young workers on how to load things properly in a basket or furnace.

Putting It All Together

Caterpillar's new program allows OEMs access to extensive manufacturing and heat treat technical expertise, acquired over many years of experience. They have a cutting edge heat treatment facility, supported by a well-trained staff, and marketed by an experienced OEM sales team. This makes a winning combination for both the OEM and Caterpillar.

Heat Treating Services

Caterpillar's modern gear factory includes a new heat treatment facility with high-tech equipment and technology,

These facilities are also at your service.

The wide variety of heat treatment processes includes carburizing (batch and press quench), gas nitriding and induction hardening. The latest in automatic atmospheric controllers ensures proper hardness gradients and microstructure.

Caterpillar Industrial Products, Inc. can analyze your needs... and offer recommendations on how to use the vast resources of Caterpillar to obtain the best possible gear quality available.

There is no charge or obligation for the initial consultation and recommendations. Just call, write or FAX for a discussion of our gear manufacturing and heat treatment services.

Caterpillar's TOTAL capabilities - at your service.

This technical information has been contributed by
Caterpillar Industrial Products, Inc.

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