Precipitation Hardening Steels

Our integrated manufacturing edge gives us the ability to produce steel in a variety of finishes, surface options and profiles

15-5PH, 17-4PH 1.4542 & 1.4594 AMS5642, DIN/EN10088-3, AMS 5622 & ASTM A564

OVERVIEW

Product Description

Precipitation Hardening stainless steels are chromium and nickel containing steels that provide an optimum combination of the properties of Martensitic and Austenitic grades. Like Martensitic grades, they are known for their ability to gain high strength through heat treatment and they also have corrosion resistance of austenitic stainless steel.

The high tensile strengths of precipitation hardening stainless steels come after a heat treatment process that leads to precipitation hardening of Martensitic or Austenitic matrix. Hardening is achieved through the addition of one or more of the elements Copper, Aluminium, Titanium, Niobium and Molybdenum.

The most well known precipitation hardening steel is 17-4 PH, the name comes from the additional 17% Chromium and 4% Nickel. It also contains 4% Copper and 0.3% Niobium, 17-4 PH is also known as stainless steel grade 630.

The advantage of precipitation hardening steels is that they can be supplied in a “solution-treated” condition, which is readily machinable, After machining or another fabrication method, a single, low-temperature heat treatment can be applied to increase the strength of the steel. This is known as aging or age-hardening. As it is carried out at low temperature, the component undergoes no distortion.

Composition limits for 17-4 PH and 15-5 PH, with their EN and UNS names, are in the precipitation hardening grade family. What each heat-treatment condition buys is set out in the precipitation hardening article.

Precipitation hardening stainless steel bars produced by Laxcon Steels

SPECIFICATION

Supply Conditions

Industry Applications: Oil, Gas, Power, Offshore, Chemical, Nuclear, Food Industry, Aerospace, Pulp and Paper Industry, High Pressure Pump and Valves Components, Measuring and Control, Mechanical Components and Welding Applications.
Standards: AMS5642, DIN/EN10088-3, AMS 5622 & ASTM A564
Grade: 15-5PH, 17-4PH / 1.4542 & 1.4594
Heat treatment conditions: Solution Annealing, H 900, H925, H1025, H1075, H1100, H1150, H1150D, H1150M

Governing standards

ASTM A564/A564M: Hot-rolled and cold-finished age-hardening stainless steel bars and shapes: the conditions A, H900 to H1150 and the properties each guarantees.
EN 10088-3: Stainless steels: technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products for general purposes. Composition, heat treatment condition and mechanical properties per grade.
AMS 5643: 17-4PH (UNS S17400) bars, forgings and rings: the aerospace material specification for the grade.
AMS 5659: 15-5PH (UNS S15500) bars, forgings and rings.
ASTM A484/A484M: General requirements for stainless steel bars, billets and forgings: permissible variations in dimensions, straightness, weight and length, and the test and marking requirements every bar order inherits.
NACE MR0175 / ISO 15156: Materials for use in H2S-containing environments in oil and gas production: the sour-service limits on hardness and condition.
EN 10204: Metallic products, types of inspection documents: the 2.2 test report and the 3.1 and 3.2 inspection certificates a purchase order can call for.

Heat treatment conditions of 17-4PH, ASTM A564

Condition	Ageing temperature	Minimum tensile strength	Minimum yield strength	Hardness (max or range)
A (solution treated)	none	not specified	not specified	363 HB max
H900	482 degrees C, 1 hour	1,310 MPa	1,170 MPa	388 HB min
H925	496 degrees C, 4 hours	1,170 MPa	1,070 MPa	375 HB min
H1025	552 degrees C, 4 hours	1,070 MPa	1,000 MPa	331 HB min
H1075	580 degrees C, 4 hours	1,000 MPa	860 MPa	311 HB min
H1100	593 degrees C, 4 hours	965 MPa	795 MPa	302 HB min
H1150	621 degrees C, 4 hours	930 MPa	725 MPa	277 HB min
H1150M	760 degrees C 2 hours, then 621 degrees C 4 hours	795 MPa	520 MPa	255 HB min

ASTM A564 minimum properties for bar in each condition; the condition number is the ageing temperature in degrees Fahrenheit. Laxcon supplies the bar solution treated (Condition A) or aged to the condition ordered.

Precipitation hardening against martensitic and austenitic grades

A martensitic stainless steel such as 420 reaches high strength by quench and temper, which distorts the part and limits corrosion resistance. An austenitic grade such as 316 has the corrosion resistance but cannot be hardened at all. 17-4PH and 15-5PH are machined soft in the solution treated condition and then aged at 480 to 620 degrees Celsius for one to four hours, which precipitates copper-rich particles through the martensitic matrix and raises the yield strength to between 725 and 1,170 MPa depending on the condition chosen, with a dimensional change of about 0.05 percent and corrosion resistance close to 304. That combination is why the family is specified for pump shafts, valve stems, aerospace fittings, gears and moulds.

What each condition buys, and the trade between strength and toughness as the ageing temperature rises, is set out in the precipitation hardening article; composition limits and the EN and UNS names are in the grade family.

Frequently Asked Questions

Which precipitation-hardening stainless steel grades are available?

Laxcon publishes 15-5 PH and 17-4 PH, including the 1.4542 and 1.4594 references, to AMS 5642, AMS 5622, ASTM A564 and DIN or EN 10088-3.

Which heat-treatment conditions are listed for PH stainless steel?

Precipitation hardening stainless steel is listed in the solution annealed condition and in H900, H925, H1025, H1075, H1100, H1150, H1150D and H1150M.

Where are precipitation-hardening steels used?

Published applications for precipitation hardening steels are oil and gas, power, offshore, chemical, nuclear, food, aerospace, pulp and paper, high-pressure pumps and valves, and mechanical or control components.

How can precipitation-hardening stainless steel bars be packed and traced?

Laxcon packs precipitation hardening stainless steel bars in standard bundles of 500 to 1,000 kg with HDPE or LDPE wrapping and two lifting slings. ISPM 15 wooden boxes and fibre-tube packing are available, and every bundle is marked with heat number, grade, size, and net and gross weight.

What should an RFQ for precipitation-hardening stainless steel bars include?

An enquiry for precipitation hardening stainless steel bars is quotable when it states the grade, governing standard, metric size or profile, tolerance, finish or heat-treatment condition, length, quantity, test or inspection requirement, and delivery destination.

CATALOGUE