Is 15-5PH the Ultimate Material for Corrosion Resistance?

┃ Overview

15-5PH stainless steel (also known as 15-5PH, UNS S51500, W.Nr. 1.4545) is a type of martensitic precipitation-hardening stainless steel. It possesses excellent strength, corrosion resistance, and mechanical properties at temperatures of up to 600°F (316°C). Furthermore, it exhibits remarkable toughness in both the longitudinal and transverse directions, making it suitable for various applications, including base metal and welds.

┃ Application

Aerospace Industry: Aircraft structural parts, landing gear, fittings, and engine parts

Chemical Processing: Pumps, valves, fittings, and heat exchangers that come into contact with corrosive chemicals

Nuclear Industry: Reactor components, control rod mechanisms, and storage containers

Marine Applications: Propeller shafts, pump shafts, fasteners, and other marine hardware

Oil and Gas Industry: Downhole tools, valves, and fittings

Medical and Pharmaceutical Equipment: Surgical instruments, orthopedic implants, and pharmaceutical processing equipment

Firearms and Defense: Barrels, receivers, and action parts

┃ Chemical Composition (%)

Material	C	Mn	P	S	Si	Cr	Ni	Cu
15-5PH	0.07max	1.00max	0.04max	0.03max	1.00max	14.0-15.5	3.50-5.50	2.50-4.50

┃ Mechanical Property

Material	Tensile strength	Yield strength 0,2	Elongation	Hardness HB30
15-5PH	930-1310N/mm²	700-1170N/mm²	10-16%	277-444HB

┃Corrosion Resistance

15-5PH stainless steel demonstrates exceptional corrosion resistance in both highly oxidizing and reducing environments, as well as when exposed to atmospheric conditions. Its corrosion resistance surpasses that of types 410 and 431, and is comparable to that of 17-4PH stainless steel. The highest level of general corrosion resistance is achieved when the material is fully hardened, although it slightly decreases as the aging temperature is raised. Furthermore, 15-5PH stainless steel can exhibit excellent resistance to stress-corrosion cracking when it is hardened at temperatures of 1025ºF (551ºC) and above. This property enhances its suitability for applications where resistance to stress corrosion cracking is crucial.

┃Heat Treatment

Typically, 15-5PH stainless steel is supplied in the solution-treated condition, known as Condition A. To achieve increased hardness, the material can be subjected to a hardening process. This involves heating the solution-treated steel to a temperature range of 900ºF (482ºC) to 1150ºF (621ºC) for a duration of one to four hours, depending on the specific temperature. Following the heating process, the steel can be cooled by either air cooling or oil quenching. For sections measuring under 3" (76 mm), oil quenching is suitable, while sections over 3" (76 mm) should be rapidly air cooled.

┃ Heating and Pickling

Heating of 15-5PH is commonly performed for heat treatment purposes. The process involves heating the material to specific temperatures and holding it for a certain duration in controlled atmospheres, and air cooling or quenching, to prevent oxidation and achieve desired mechanical propertie, improve strength and hardness. Post-treatment processes may be necessary to meet the final product specifications.

Pickling is a common process used to remove surface impurities and oxide layers from 15-5PH. It involves immersing the material in a pickling solution, typically an acid-based solution, to dissolve contaminants and restore the material's corrosion resistance.

┃ Hot and Cold Forming

15-5PH stainless steel can be formed through both hot forming and cold forming processes, each offering distinct advantages.

Hot forming takes advantage of the material's increased ductility when heated, allowing for easy shaping of complex forms without the risk of cracking, particularly at high temperatures. Methods such as hot rolling, forging, and hot extrusion are commonly used for larger and intricate components that require extensive deformation.

On the other hand, cold forming utilizes the inherent ductility of 15-5PH stainless steel, enabling precise shaping, tight tolerances, and improved surface finish. Cold forming methods like cold rolling, cold drawing, bending, and deep drawing are preferred for smaller and simpler components or those requiring high dimensional accuracy and surface quality. Additionally, cold forming improves the strength and hardness of the material through work hardening during the process.

┃Machining

Machining 15-5PH stainless steel is easily accomplished in both the solution-treated and various age-hardened conditions. In the solution-treated condition, its machinability is similar to that of stainless steel types 302 and 304. However, in age-hardened conditions, the machinability improves as the hardening temperature is increased.

┃Welding

The weldability of 15-5PH stainless steel is comparable to that of 17-4PH stainless steel, allowing for successful welding using common shielded fusion and resistance welding techniques. To match the properties of the base metal, it is recommended to use AWS E/ER630 welding consumables as filler metal. However, oxyacetylene welding should be avoided due to the potential for carbon pickup in the weld. In the solution-treated condition, the material can be directly aged after welding to achieve the desired strength level, streamlining the post-welding process.

┃ Product Forms

Ø Bar & Rod

Ø Plate & Sheet

Ø Coil & Strip

Ø Pipe & Tube

Ø Fitting: Flange, Tee, Elbow, Reducer etc.

Ø Forging: Ring, Shaft, Circle, Block etc.

┃ Note

Ronsco is a supplier with more than 27 years of experience in the special metal field, we always adheres to the business phiosophy of "customer-centered", tries its best to meet the requirements of customers and pursues win-win cooperation with customers. Are you looking for special metal products one-stop supplier! Contact Us Now! Email: marketing@ronsteel.com