Carpenter Technology’s Custom 465® stainless steel (UNS S46500) is a premium double vacuum-melted, martensitic, age-hardenable alloy that offers a unique combination of high strength, toughness, and corrosion resistance. When the alloy was first introduced to the aerospace industry in 1997, its developers felt that the alloy’s properties were so exceptional that they would be of value to other industries as well.
The alloy has greatly exceeded their expectations, finding myriad applications in diverse industries. While the alloy continues to meet the special and exacting needs of aerospace manufacturers, it also has found application in marine equipment, firearms, hand tools, oil and gas drilling, and the medical industry among others.
The H950 condition (510ºC) is most commonly used to get higher strength together with good toughness and excellent notch tensile strength. The H1000 condition (538ºC) is chosen to obtain increased toughness at a slightly lower strength level. This condition provides a superior combination of strength, toughness, fabricability, and stress corrosion cracking resistance when compared to other high strength PH stainless alloys such as Custom 455 stainless (UNS S45500) and 13-8 stainless (UNS S13800).
General corrosion resistance of Custom 465 stainless approaches that of 304 stainless. In both the H950 and H1000 conditions, exposure to 5% neutral salt spray at 95ºF (35º C) (per ASTM B117) caused no rusting after over 2000 hours. Double-cantilever-beam tests conducted in 3.5% NaCl (pH 6) show Custom 465 stainless to possess inherently good resistance to stress corrosion cracking.
Conditions for Use
In today’s competitive business climate, there is a growing list of manufacturers who are focused on lowest life cycle cost, rather than lowest initial cost. This attitude has created a strong worldwide demand for materials options possessing high strength and toughness, having relative ease of fabrication, and providing reliable, long-term service in corrosive environments. Custom 465 stainless can fill all these needs at once.
The patented alloy has been used as a corrosion resistant upgrade to high strength alloy steels, and as a higher strength upgrade to more conventional stainless steels. Unlike alloy steels, Custom 465 stainless requires no surface coating or metal plating to provide corrosion resistance. It thus eliminates the vulnerability of treated surfaces to cracking and subsequent corrosion attack.
In addition to the expense of coating or plating, the environmental issues related to such coatings and their waste solution disposal are an even larger problem. The European Union, for example, is considering a ban on cadmium plating. Even if Cd plating is not entirely banned, new restrictions and regulations could make the cost of disposing used plating baths prohibitive.
A superior strength-to-weight ratio has driven the success of several new products beyond aerospace. The very high levels of strength that can be achieved provide the part designer with the opportunity to either add strength to an existing design or to reduce its weight or size. Even with such high strength levels, Custom 465’s superior fabricability has been key to the success of critical products that could not be made from alternative high strength materials.
The material is typically shipped from the mill in a solution annealed and cold treated condition. In this condition, Custom 465’s structure is a highly ductile iron-nickel martensite with low yield strength and a relatively low rate of work hardening. As such it can easily be formed or shaped via conventional methods before the simple one-step hardening treatment.
Its stress corrosion resistance, furthermore, improves with increasing aging temperature. It is comparable to that of 13Cr-8Ni stainless and Custom 455 stainless steels, but at significantly higher strength – and its resistance is superior to that of both when overaged to the same strength level. Fig. 5 displays the relative strength, general corrosion resistance, and stress corrosion cracking resistance of traditional PH stainless steels.
Precision Alloy Services is a specialty metals distributor and processor located in Bowling Green, Ohio. Precision Alloy Services quality management system is certified to ISO 9001:2015 and AS9100 Rev D, and we carry a large inventory of materials including nickel, cobalt, aluminum and titanium alloys, stainless steels and specialty alloy steels in a variety of sizes of sheet, plate, bar, and wire. Processing includes bar sawing, water-jet cutting, chamfering and other services. Contact Us for more information.
Custom 455 Stainless Alloy | Custom 465 Stainless Alloy | Biodur 316LS Stainless, 316LVM, ASTM F138 Stainless | 17-4 alloy stainless steel, ASTM F899