|
Flame Hardening for Crawler Shoes |
|
Written by Andy Kruse, Process Engineer
|
|
Wednesday, 08 April 2009 00:54 |
|
SPOKANE INDUSTRIES, through its Spokane Steel Foundry, Spokane Metal Products and Spokane Precision Castings operations, has been providing customers around the world with cost effective solutions to their steel castings and industrial fabrication needs since 1952. Today, SPOKANE INDUSTRIES is a modern diversified company with plant and manufacturing facilities occupying more than 240,000 square feet. The company serves a large number of customers in many industries -- from aerospace, construction and agriculture, to transportation, aggregate processing, and manufacturing. To serve these customers and industries, we utilize in-house engineers to continually improve our processes and the quality of our products.
by AndyKruse,ProcessEngineer
SPOKANE INDUSTRIES, through its Spokane Steel Foundry, Spokane Metal Products and Spokane Precision Castings operations, has been providing customers around the world with cost effective solutions to their steel castings and industrial fabrication needs since 1952. Today, SPOKANE INDUSTRIES is a modern diversified company with plant and manufacturing facilities occupying more than 240,000 square feet. The company serves a large number of customers in many industries -- from aerospace, construction and agriculture, to transportation, aggregate processing, and manufacturing. To serve these customers and industries, we utilize in-house engineers to continually improve our processes and the quality of our products.
Process Engineering is an important part of any quality manufacturing organization. At Spokane Industries, we are continually looking for those processes that can be improved to reduce costs and improve efficiencies. Sometimes, the process is unique to a single part for only one customer. Engineering time to improve processes even for a single part can be very beneficial for the entire supply chain as improvements made on a single steel casting holds down costs and reduces lead times for all.
Spokane Steel Foundry currently produces for a large mining equipment manufacturer, a crawler shoe steel casting . The steel casting requirements call for flame hardening in the high wear roller path areas. A basic, manual cell was constructed whereby a pair of operators with hand-held torches heated the specified area before quenching in a tank of water. As production expanded, the cell as designed could not support the growing volumes. Also, these increasing orders accelerated the need to drive costs down throughout our manufacturing processes. Revisiting the work flow in this flame-hardening cell has led to increased efficiencies making this process more predictable, streamlined, and repeatable. Through a series of trials and redesigns of the fixture, we established a design that was ultimately the most efficient.
The engineering team at Spokane Steel Foundry wanted to insure the process produced consistent results from part to part. The area to be flame hardened is quickly austenitized at a temperature above the Ac3 as determined by its chemistry and initial microstructure. After holding for a pre-determined time, the casting is immediately quenched in water at a controlled temperature and agitation. Hardness is verified at the surface and at the maximum depth required. The casting is hoisted into the fixture. The fixture was engineered so that we could take advantage of efficiencies of having it located directly above the quench tank " thus short time lapse between heat and quench. The advantage of having the steel casting in a fixture is that it allows the torch tips to be stationary and generates a consistent flame pattern on the steel casting.
The improvements in fixture design contain multiple fixed torch heads oriented so that the specified areas of the steel casting would be flame hardened in the exactly the same location every time. We adjusted the number of tips in the fixture putting the optimal number of BTUs into the steel casting. This engineered fixture keeps the torch heads a uniform distance from torch tip to steel casting and subsequently reduces wasted flame time and removes operator error.
The engineering changes mentioned also reduced the cycle time and the flame to quench time in this process. This Research and Development has now gives us complete control of our repeatable process of flame hardening giving us the desired hardened result every time.
Tim Wade, Engineering Manager for Spokane Steel Foundry is proud of the work accomplished by the process engineers working on these changes. In the steel casting process, Spokane Industries, through our Spokane Steel Foundry Division must find better ways to produce customer parts to stay competitive in this global economy. By taking a workable cell and making it more efficient drives out costs and gives a higher and more consistent quality of part. We will continue to look for more areas where we can make similar improvements with either single part processes or where a family of parts can benefit.
Information:
For more information on Spokane Industries or to inquire about how Spokane Steel Foundry can help you with your steel castings needs, please visit our web site at www.SpokaneIndustries.com or call us at 1-800-541-3601 and ask for steel castings sales. |
