A Full Range of Capabilities Supporting Alloy Development through Production
When faced with a need for new material solutions, ATI Powder Metals is the ideal partner for developing a new or improved powder metal product and scaling up to production. ATI Powder Metals is the industry's only fully-integrated manufacturer of nickel-base superalloys, performing on-site atomization through hot isostatic pressing (HIP). Through a full range of atomizers, alloys can be produced in heat sizes ranging from one pound up to 8,000 lb. in the world's largest vacuum induction melt (VIM) inert gas atomizer designed and built by ATI Powder Metals. Regardless of scale, the process maintains powder cleanliness from start to finish to assure optimal quality.
Atomization
A full range of atomizers assure a heat size that matches your production and metallurgy needs.
Vacuum Induction Melt, Inert Gas Atomizers
- Ni, Co, Fe, Cu, Cr and other specialized alloys
- Laboratory atomizer for alloy development and small batch production
- Intermediate atomizer for production scale-up and low rate production
- Large atomizers capable of high volume production
- Ti alloys
- Refractory free skull melting
- From small batches to large volume production
Screening
Screening is performed to classify powder to a desired size range, down to a maximum particle size of 45 microns (-325 mesh). For applications requiring finer powder, other separation methods can be employed. ATI Powder Metals employs multiple screening systems in order to process several alloys simultaneously.
- Standard screening from 1180µm (16 mesh) to 45µm (325 mesh)
- Finer powder sizes attained by screening or air classification
Hot Isostatic Pressing (HIP)
Laboratory size and full-scale HIP vessels are in service to support development through production.
- Laboratory size vessel
- Working zone of 7.5" dia x 13" high
- Up to 2375° F & 28,000 psi
- Full-scale vessel
- Working zones of 43" dia x 110" high or 51" dia x 115" high
- Up to 2250° F & 15,000 psi
The Process
ATI Powder Metals' process utilized to produce HIP-consolidated PM material consists of the following 6 basic process steps, as detailed below.
Atomization
The process begins with the production of powder, utilizing vacuum inducting melting (VIM) coupled with inert gas atomization (IGA). Identical to conventional ingot metallurgy, the desired composition is achieved in the melt furnace, and after refining, rather than pouring the molten metal into molds or ingots, the material is diverted through a nozzle and the resulting stream is impinged by high velocity inert gas. This event results in rapid solidication of the metal, eliminating segregation during cooling, and the powder particles are collected for subsequent processing. Each individual powder particle shares a common chemistry, and can be thought of as a "micro-ingot".
Screening
Following atomization, which yields a wide size range of powder particles, powder is screened to a desired particle size distribution based on the particular application. Screening is done in a clean room environment under a positive pressure of filtered air. Further powder classification can be accomplished by air classification, used to separate the very fine powder particels (<20µm).
Blending
Following screening, the yield of multiple heats are blended together under vacuum to improve homogeneity of composition and the particle size distribution. The latter is of paramount concern in the production of near-net-shape products due to the influence on packing density of the powder and therefore the extent of distortion realized during consolidation.
Loading
Mild steel or stainless steel containers, custom-engineered based on desired finish dimensions and TIG-welded for optimum integrity, are filled with powder under vacuum or in other controlled environments. The containers are vibrated during loading to maximize packing density.
Outgassing
Loaded containers are connected to vacuum pumps and heat is applied. This computer-controlled process removes residual gases and moisture from the compacts, preventing the formation of deleterious oxides etc. during consolidation. Upon completion of this process, the containers are sealed and transferred for HIP.
Hot Isostatic Pressing (HIP)
The outgassed and hermetically sealed containers are loaded into the autoclave with other available parts that share common processing parameters, then high temperature and pressure are simultaneously applied for a predetermined period of time to ensure full consolidation. HIP consolidation yields material exhibiting full theoretical density.
