Kittyhawk Products Inc.

Hot Isostatic Processing (HIP) is fast becoming an industry standard. Due to increasingly complex specification, higher demands on quality and lowing HIP costs, hot isostatic processing has matured to a stage where it is universally recognized and is used on an industrial scale. It is now used in the aerospace, commercial, military, medical, automotive, and recreational industries. Education in the application and benefits of hot isostatic processing is essential for further development.

Hot Isostatic Processing is a process in which components are subjected to the simultaneous application of heat and high pressure in an inert gas medium. The pressure is uniform in all directions or isostatic. HIP is a production process of unique benefit in solving precision and complex casting and manufacturing needs. The major commercial activity centers on the consolidation of powder metals, the densification of high performance castings, diffusion bonding of similar and dissimilar metals and rejuvenation of fatigue-damaged parts. It improves the performance and yield of precision castings.

There is a great need for design engineers, as well as production personnel, to educate themselves about and taking advantage of the benefits of the HIPing process. This will assist in keeping up to the increasing demands on quality design and costs in the industry. Education is a priority at Kittyhawk products. We have an expert team available for consultation and we provide free HIPing services for test parts so that we can acquaint engineers with what HIP will do for them. HP is no longer seen as a crutch to fix castings but as an integral step to improve castings, supplying customers with the best quality possible. Hot isostatic processing is seen as a process to improve yields rather than last resort salvage operation.

One of the reasons for using HIP is to get the competitive edge in your field. Quality is always highly regarded among buyers. As a manufacturers’ standards increase, HIP has become a necessary tool for foundries to deliver the required product. HIP can be used to reduce rework and machining costs and, as labor costs escalate, any process that can reduce direct labor is an asset. Expensive retooling can be avoided. When the requirements for castings increase, HIP can be used to increase the grade of your particular casting. Although HIP is not as substitute for poor casting practices, the integration of castings and HIP can reduce material and processing costs.

Hot Isostatic Processing is buying insurance for your castings. You don’t want to be insurance poor but there are instances when insurance makes sense.

Cast alloys are subject to defects that generally result in their having lower more variable mechanical properties than their wrought counterparts. These defects include shrinkage, inclusions and alloy segregation. Reasonable control is possible by proper mold design and good foundry practice. However, the complete elimination of all defects from cast shapes is not possible without applying some external force to accomplish the deformation necessary to close voids and porosity. HIP provides the ideal mechanism for the application of this force, combining heat and pressure to collapse voids and porosity by creep mechanisms and to ‘heal’ the material by diffusion bonding the material together. Void closure is accomplished with a usually immeasurable, dimensional distortion resulting in improved reliability of the casting. Pieces of extremely complex geometry can be treated without the use of expensive tooling.

The many investigations conducted on several classes of cast material show that HIP results in startling improvements in mechanical properties. The effects of HIPing on mechanical properties are higher strength, higher toughness, longer fatigue resistance and longer creep life. The greatest significance of the HIP process is the marked reduce in the statistical spread or scatter usually associated with the cast material. The net result is improved efficiency of the material utilization in the casting and the ability to use castings for applications formerly requiring more forged or wrought and machined materials to meet specifications.

In many engineering applications the response to a fatigue environment is critical to material and processing route selection. Any increase in porosity content reduces fatigue capability and the elimination of porosity with HIPing, in turn, improving fatigue life and tensile properties.

By incorporating hot isostatic processing as part of the manufacturing process, casting producers and end users are beginning to reap many benefits. Production yields are increased as the use of HIPing grows. Perhaps most important, casting manufacturers who use HIP are experiencing greater freedom in producing their products. Mold design can be simplified to save material formerly used in complex gating, and the placement of chills becomes less critical.

Also, alloys once considered uncastable because of problems with hot tears or the formation of undesirable phases during solidification, now can be resolved by HIP. In other words, a concept of cast-to-fill and HIP-to-density can be developed to take full advantage of more exotic materials.

In the end, everything comes back to the cost of a part and for this reason treatment of this topic is at the beginning and end of all discussions of HIP castings. As with most newly developed processes, costs were initially high. As a result, most work using the process involved only very expensive and difficult-to-fabricate materials and generally was limited to a few relatively low-volume applications. A significant reduction in the costs has occurred in recent years. Evidence has shown that major cost savings have been achieved with hot isostatic processing and HIPing can now be used as an integral part in savings costs down the production line. If a casting is rejected after the machining process it is the manufacturer that loses the most because he cannot recover valuable scheduling time and the costs of the machining step. By the time the part is found to be unacceptable due to flaws or low mechanical properties, one has spent a considerable amount manufacturing costs, which often far exceeds the original costs of the casting. The HIP industry now can accommodate high and low-volume users alike by piggybacking many customers into one cycle of the larger HIP units. The per pound pricing of this method makes the process affordable even to the smallest investment foundries.

While the extent of HIP application cannot yet be defined, the demonstrated benefits make it important to identify areas where quality improvement and cost advantages might be realized. Kittyhawk Products continue to reach out to different industries through their research and development departments to help others discover the benefits of hot isostatic processing, as we enter the 21st century.


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		Hot Isostatic Processing in the 21st Century *Hot Isostatic Processing (HIP)* is fast becoming an industry standard. Due to increasingly complex specification, higher demands on quality and lowing HIP costs, hot isostatic processing has matured to a stage where it is universally recognized and is used on an industrial scale. It is now used in the aerospace, commercial, military, medical, automotive, and recreational industries. Education in the application and benefits of hot isostatic processing is essential for further development. Hot Isostatic Processing is a process in which components are subjected to the simultaneous application of heat and high pressure in an inert gas medium. The pressure is uniform in all directions or isostatic. HIP is a production process of unique benefit in solving precision and complex casting and manufacturing needs. The major commercial activity centers on the consolidation of powder metals, the densification of high performance castings, diffusion bonding of similar and dissimilar metals and rejuvenation of fatigue-damaged parts. It improves the performance and yield of precision castings. There is a great need for design engineers, as well as production personnel, to educate themselves about and taking advantage of the benefits of the HIPing process. This will assist in keeping up to the increasing demands on quality design and costs in the industry. Education is a priority at Kittyhawk products. We have an expert team available for consultation and we provide free HIPing services for test parts so that we can acquaint engineers with what HIP will do for them. HP is no longer seen as a crutch to fix castings but as an integral step to improve castings, supplying customers with the best quality possible. Hot isostatic processing is seen as a process to improve yields rather than last resort salvage operation. One of the reasons for using HIP is to get the competitive edge in your field. Quality is always highly regarded among buyers. As a manufacturers’ standards increase, HIP has become a necessary tool for foundries to deliver the required product. HIP can be used to reduce rework and machining costs and, as labor costs escalate, any process that can reduce direct labor is an asset. Expensive retooling can be avoided. When the requirements for castings increase, HIP can be used to increase the grade of your particular casting. Although HIP is not as substitute for poor casting practices, the integration of castings and HIP can reduce material and processing costs. Hot Isostatic Processing is buying insurance for your castings. You don’t want to be insurance poor but there are instances when insurance makes sense. Cast alloys are subject to defects that generally result in their having lower more variable mechanical properties than their wrought counterparts. These defects include shrinkage, inclusions and alloy segregation. Reasonable control is possible by proper mold design and good foundry practice. However, the complete elimination of all defects from cast shapes is not possible without applying some external force to accomplish the deformation necessary to close voids and porosity. HIP provides the ideal mechanism for the application of this force, combining heat and pressure to collapse voids and porosity by creep mechanisms and to ‘heal’ the material by diffusion bonding the material together. Void closure is accomplished with a usually immeasurable, dimensional distortion resulting in improved reliability of the casting. Pieces of extremely complex geometry can be treated without the use of expensive tooling. The many investigations conducted on several classes of cast material show that HIP results in startling improvements in mechanical properties. The effects of HIPing on mechanical properties are higher strength, higher toughness, longer fatigue resistance and longer creep life. The greatest significance of the HIP process is the marked reduce in the statistical spread or scatter usually associated with the cast material. The net result is improved efficiency of the material utilization in the casting and the ability to use castings for applications formerly requiring more forged or wrought and machined materials to meet specifications. In many engineering applications the response to a fatigue environment is critical to material and processing route selection. Any increase in porosity content reduces fatigue capability and the elimination of porosity with HIPing, in turn, improving fatigue life and tensile properties. By incorporating hot isostatic processing as part of the manufacturing process, casting producers and end users are beginning to reap many benefits. Production yields are increased as the use of HIPing grows. Perhaps most important, casting manufacturers who use HIP are experiencing greater freedom in producing their products. Mold design can be simplified to save material formerly used in complex gating, and the placement of chills becomes less critical. Also, alloys once considered uncastable because of problems with hot tears or the formation of undesirable phases during solidification, now can be resolved by HIP. In other words, a concept of cast-to-fill and HIP-to-density can be developed to take full advantage of more exotic materials. In the end, everything comes back to the cost of a part and for this reason treatment of this topic is at the beginning and end of all discussions of HIP castings. As with most newly developed processes, costs were initially high. As a result, most work using the process involved only very expensive and difficult-to-fabricate materials and generally was limited to a few relatively low-volume applications. A significant reduction in the costs has occurred in recent years. Evidence has shown that major cost savings have been achieved with hot isostatic processing and HIPing can now be used as an integral part in savings costs down the production line. If a casting is rejected after the machining process it is the manufacturer that loses the most because he cannot recover valuable scheduling time and the costs of the machining step. By the time the part is found to be unacceptable due to flaws or low mechanical properties, one has spent a considerable amount manufacturing costs, which often far exceeds the original costs of the casting. The HIP industry now can accommodate high and low-volume users alike by piggybacking many customers into one cycle of the larger HIP units. The per pound pricing of this method makes the process affordable even to the smallest investment foundries. While the extent of HIP application cannot yet be defined, the demonstrated benefits make it important to identify areas where quality improvement and cost advantages might be realized. Kittyhawk Products continue to reach out to different industries through their research and development departments to help others discover the benefits of hot isostatic processing, as we enter the 21st century.