Crucible Materials Corporation
Contact: Sales Manager
5639 West Genesee St
Camillus, NY 13031-0991
U.S.
Phone: (315) 487-0800 (800)
Fax: (315) 487-4028
CPMCrucible Particle Metallurgy
The proprietary Crucible Particle Metallurgy (CPM®) process has been used for the commercial production of high speed steels and other high alloy tool steels since 1970. The process lends itself not only to the production of superior quality tool steels, but to the production of higher alloyed grades which cannot be produced by conventional steelmaking. For most applications the CPM process offers many benefits over conventionally ingot-cast tool steels.
Conventional Steelmaking vs.Particle Metallurgy Processing
Conventional steelmaking begins by melting the steel in a large electric arc furnace. It is usually followed by a secondary refining process such as Argon Oxygen Decarburization (AOD). After refining, the molten metal is poured from the furnace into a ladle, and then teemed into ingot molds.
Although the steel is very homogeneous in the molten state, as it slowly solidifies in the molds, the alloying elements segregate resulting in a non-uniform as-cast microstructure. In high speed steels and high carbon tool steels, carbides precipitate from the melt and grow to form a coarse intergranular network. Subsequent mill processing is required to break up and refine the microstructure, but the segregation effects are never fully eliminated. The higher the alloy content and the higher the carbon content, the more detrimental are the effects of the segregation on the resultant mechanical properties of the finished steel product.
The CPM process also begins with a homogeneous molten bath similar to conventional melting. Instead of being teemed into ingot molds, the molten metal is poured through a small nozzle where high pressure gas bursts the liquid stream into a spray of tiny spherical droplets. These rapidly solidify and collect as powder particles in the bottom of the atomization tower. The powder is relatively spherical in shape and uniform in composition as each particle is essentially a micro-ingot which has solidified so rapidly that segregation has been suppressed. The carbides which precipitate during solidification are extremely fine due to the rapid cooling and the small size of the powder particles. The fine carbide size of CPM steel endures throughout mill processing and remains fine in the finished bar.
The powder is screened and loaded into steel containers which are then evacuated and sealed. The sealed containers are hot isostatically pressed (HIP) at temperatures approximately the same as those used for forging. The extremely high pressure used in HIP consolidates the powder by bonding the individual particles into a fully dense compact. The resultant microstructure is homogeneous and fine grained and, in the high carbon grades, exhibits a uniform distribution of tiny carbides. Although CPM steels can be used in the as-HIP condition, the compacts normally undergo the same standard mill processing used for conventionally melted ingots, resulting in improved toughness.
CPM Eliminates Segregation
Conventionally produced high alloy steels are prone to alloy segregation during solidification. Regardless of the amount of subsequent mill processing, non-uniform clusters of carbides persist as remnants of the as-cast microstructure. This alloy segregation can detrimentally affect tool fabrication and performance.
CPM steels are HIP consolidated from tiny powder particles, each having uniform composition and a uniform distribution of fine carbides. Because there is no alloy segregation in the powder particles themselves, there is no alloy segregation in the resultant compact. The uniform distribution of fine carbides also prevents grain growth, so that the resultant microstructure is fine grained.
Advantages of CPM
For the End User:
Higher Alloy Grades Available
Improved Wear Resistance
Improved Toughness (less chipping)
Consistent Tool Performance
Good Grindability (on resharpening)
For the Tool Manufacturer:
Consistent Heat Treat Response
Predictable Size Change on Heat Treat
Excellent, Stable Substrate for Coatings
Excellent Grindability
Improved Machinability (w/sulfur enhancement)
Efficient Wire EDM Cutting
Applications for the Plastics Industry
Crucible's P/M process yields HIP clad twin screw barrel blanks wich combine superior wear and corrosion resistance. Bi-metallic wear resistant screw segments offer the superior performance and long life cycles demanded in the plastics industry.
Crucible's advanced P/M technology provides components with superior wear and corrosion resistance for demanding applications in the plastics industry.
Crucible components for the plastics industry, made by advanced Hot lsostatic Pressing (HIP) technology or hot extrusion, offer advantages over traditional centrifugally cast or welded components. Crucible components offer superior wear and corrosion resistance, for outstanding performance in the demanding environments of the plastics industry. HIP provides a fully dense material, and a metallurgical bond between the liner and base alloy in HIP clad applications.
Crucibles CPM® alloys are compatible with most base alloys used in todays barrels. When wear resistance is the primary concern, Crucible Particle Metallurgy (CPM) 1OV® and 9V are used. CPM® 44OV, MPL-1, 42OV, and various cobalt and nickel base alloys are used for applications which require both superior corrosion resistance and wear resistance.
One of the fastest growing uses of HIP products in the plastics industry is clad segmented screw blanks which are used in high torque applications where a ductile core is desirable. The segmented screw blanks are produced by inserting a low alloy steel hollow bar into a wear resistant or wear/corrosion resistant hollow bar and metallurgically bonding the two bars by HIP (see illustration above). Single and twin screw segments are produced by cladding the ID bores of a drilled low alloy steel block with wear resistant or wear/corrosion resi5tant alloy powder using a HIP process (see illustration at left and below).
Regardless of the final part type, Crucibles wear resistant and wear/corrosion resistant alloys provide unequalled service life at a reasonable price.
CPM® 9V
CPM 9V is designed for use in tooling which encounters severe wear. Its toughness (cracking resistance) is higher than other high-wear resistant cold work tool steels permitting it to be used in some applications where CPM 10V, D2 or high speed steels do not have sufficient resistance to cracking. It is usually limited in hardness to about 56 HRC or lower, and is therefore not intended for applications requiring high compressive strength.
CPM® 10V
(AISI A11)
CPM 10V is a unique tool steel made by the Crucible Particle Metallurgy process. It is designed with a tough, air hardening base analysis with added high carbon and vanadium for exceptionally good wear resistance, toughness and strength for cold and warm work tooling applications.
The exceptional wear resistance and good toughness of CPM 10V make it an excellent candidate to replace carbide and other highly wear resistant materials in cold work tooling applications, particularly where tool toughness is a problem or where cost effectiveness can be demonstrated.
CPM® 15V
CPM 15V is Crucibles highest vanadium, abrasion resistant CPM tool steel. It contains 50% more hard vanadium carbides in its microstructure than CPM 10V, to provide even higher wear resistance.
CPM 15V is intended for applications requiring exceptional wear resistance. Applications where CPM 10V is successful, but even longer tool life is desired, or applications where sintered carbide tooling is prone to fracture or difficult to fabricate, are likely to be well-served by CPM 15V.
CRUCIBLE 440C
(AISI 440C)
Crucible 440C is a heat treatable stainless steel, designed for a combination of high wear resistance and moderate corrosion resistance in mild environments.
Cru-Clad
Cru-Clad is a unique bimetalic product made by Crucible Compaction Metals which uses a proprietary process to HIP clad CPM alloys to the ID or OD of low alloy or carbon steel components. Cru-Clad products are used in engineered applications where highly wear-resistant surfaces are required in combination with relatively soft ductile substrates. Because of the flexibility of the process, Cru-Clad products can be made in a wide variety of grades, shapes and sizes. Cru-Clad screws and barrels are used in the plastic injection molding industry. Cru- Clad screw segments are used in high torque applications where wear-resistant flights and lands are required but a relatively soft ductile core is desired. Cru-Clad barrels provide an economical Iong-lasting solution to a demanding wear application.
The Cru-Clad process produces metallurgically bonded bi-metallic components which have longer lives and improved productivity over centrifugally cast or welded overlay parts. Cru-Clad components may be more economical than parts produced entirely from the wear resistant alloys. Typical Cru-Clad grades are CPM 9V, 10V, 15V, 420V and MPL-1. Other alloys are available and may be appropriate depending on the specific application.
