PH & Duplex Steels

15-5 PH Stainless Steel

Specification: AMS 5862, AMS 5659, AMS 5826, ASTM A 564, ASTM SA 564, ASTM A 693,ASME SA 693, ASTM A 705,ASME SA 705

15-5PH Precipitation Hardening Stainless Steel Alloy (S15500) is a variant of the older 17-4 PH (S17400) chromium-nickel-copper precipitation hardening stainless steel. Both alloys exhibit high strength and moderate corrosion resistance. High strength is maintained to approximately 600°F (316°C). The 15-5 PH alloy was designed to have greater toughness than 17-4 PH, especially in the through-thickness (short transverse) direction. This improved toughness is achieved by reduced delta ferrite content and control of inclusion size and shape. The composition and processing of 15-5 PH alloy is carefully controlled to minimize its content of delta ferrite, which is present in the 17-4 PH stainless steel material. Inclusion control is done by consumable electrode remelting using the electro-slag remelting (ESR) process. The 15-5 PH alloy is martensitic in structure in the annealed condition and is further strengthened by a relatively low temperature heat treatment which precipitates a copper containing phase in the alloy. Like the 17-4PH alloy, the 15-5 PH stainless steel alloy requires only a simple heat treatment; a one step process conducted at a temperature in the range 900°F (482°C) to 1150°F (621°C) depending on the combination of strength and toughness desired. A wide range of properties can be produced by this one step heat treatment. Heat treatment in the 900°F (482°C) range produces highest strength, although slightly less than those of semi-austenitic alloys like S17700 (17-7 PH) or S15700 (15-7 PH). The latter precipitation hardening alloys generally require more steps to complete heat treatment. The15-5 PH alloy is generally better-suited for plate applications than are the semi austenitic alloys.

MECHANICAL PROPERTIESPER 15-5 PH AMS 5659, AMS 5862

15-5 PH Condition
A 		Condition
H 900 		Condition
H 1075 		Condition
H 1150
0.2% Offset
Yield Strength 		psi 110,000 175,000 135,000 125,000
(MPa) 760 1,200 930 860
Ultimate Tensile
Strength 		psi 150,000 195,000 155,000 145,000
(MPa) 1,030 1,340 1,070 1,000
Elongation
(percentage in 2")		 8 15 15 15
Hardness
Rockwell C scale 		33 43 31 28

17 - 4 PH Stainless Steel

Specification: AMS 5604, AMS 5622, AMS 5643, AMS 5825, AMS 5827, AMS 7474, ASTM A 564, ASME SA 564, ASTM A 693, ASME SA 693, ASTM A 705, ASME SA 705

17-4PH Precipitation Hardening Stainless Steel Alloy (S17400), Type 630, is a chromium-nickel-copper precipitation hardening stainless steel used for applications requiring high strength and a moderate level of corrosion resistance. High strength is maintained to approximately 600°F (316°C).The 17-4 PH stainless steel alloy is martensitic in structure in the annealed condition and is further strengthened by a low temperature treatment which precipitates a copper containing phase in the alloy. In comparison to many alloys in the precipitation hardening family, the S17400 (17-4 PH) alloy requires a simple heat treatment; a one step process conducted at a temperature in the range 900°F (482°C) to 1150°F (621°C) depending on the combination of strength and toughness desired. A wide range of properties can be produced by this one step heat treatment.

MECHANICAL PROPERTIESPER 17-4 PH AMS 5643, AMS 5604

Condition Yield Strength Ultimate Tensile Strength Elongation (%) (Rockwell)Hardness
A psi 110,000 MPa 760 psi 150,000 MPa 1,030 8 33 (C)
H 950 psi 180,000 MPa 1,240 psi 195,000 MPa 1,340 10 43 (C)
H 1075 psi 160,000 MPa 1,100 psi 190,000 MPa 1,310 10 42 (C)
H 1150 psi 160,000 MPa 1,100 psi 190,000 MPa 1,310 10 42 (C)

PH13-8MO

Specification: AISI 632, AMS 5629, AMS 5864, ASTM A564, ASMT A693, ASTM A705, UNS S13800, XM-13

General

13-8 Stainless Steel [PH 13-8 Mo (tm),Vasco13-8 (tm)(UNS S13800) is a precipitation hardening stainless steel that combines excellent strength, good toughness, and good general corrosion resistance. It is a through-hardening alloy, which allows it to be used in parts with large cross sections, where yield strengths in excess of 200 ksi. (1,380 MPa) may be required. Good transverse toughness properties are achieved by tight chemical composition control (to prevent the formation of delta phase), low carbon content (to minimize grain boundary precipitation), and double vacuum melting (to reduce alloy segregation). Since the rate of cooling from the solution temperature is not critical, large cross sections can be air-cooled. This alloy is produced by a primary vacuum induction melt process (VIM), followed by a consumable vacuum arc remelting (VAR) step. Typical uses are aircraft parts, rocket engine mounts, nuclear reactor parts, landing gear components, high performance shafts, and petrochemical parts that require high strength combined with good resistance to stress corrosion.

Specifications

PH 13-8 Mo AMS 5629 - Bars, forgings, rings, and extrusions
PH 13-8 Mo AMS 5864 - Plate

Physical properties

Melting Range: 2,560 to 2,680F (1,404 to 1,471C)
Density: 0.279 lbs/in3

Heat Treatment

Solution treatment from 1,675 to 1,725F (913 to 941 C) for 15 to 30 minutes at temperature. Air cool or oil quench to below 60F (15C) to ensure complete transformation to martensite. Aging is normally carried out from 950 to 1,150F (510 to 621C), depending upon the desired final properties. Heat treatment is usually performed in air. Heat treatment of brazed components maybe done in inert atmospheres. Reducing atmospheres should not be used because of the potential for nitrogen contamination.

HARDNESS

Hardness in the solution annealed condition is approximately Rockwell C 33.

OXIDATION AND CORROSION RESISTANCE

PH13-8MO alloy has excellent oxidation resistance up to 1,500F (816C). Corrosion resistance decreases slightly as the aging temperature is raised. This alloy has the best resistance to stress corrosion cracking of all of the precipitation hardenable stainless steels. Its resistance to general corrosion is greatest in the fully-hardened condition. The alloy shows very little rusting when exposed to a 5 percent salt fog at 95F (35C).

FORGEABILITY/ FORMABILITY

PH13-8MO alloy has good hot working characteristics, and can be forged over a wide temperature range. Temperatures up to 2,200°F(1,204C) may be used. For optimum properties, forging temperature should not exceed 1,900F(1,038C). Hot working shouldnot be done below 1,700F (927C). After forging, parts should be cooled to room temperature, then solution treated prior to aging.The alloy can be cold formed in the annealed condition, utilizing conventional cold forming techniques.

MACHINABILITY

PH 13-8 MO alloy can be machined in both the annealed and hardened conditions. In the annealed condition, use machine speeds 20 to 30 percent lower than those used on 304 stainless steel.

WELDABILITY

PH13-8MO alloy is normally welded using inert gas tungsten arc techniques, although most other welding processes may be used. These include plasma arc, electron beam, gas metal arc, and shielded metal arc processes. Helium is the preferred shielding gas.

SPECIAL PRECAUTIONS

All lubricants and coolants, particularly sulfur-bearing, should be removed prior to heat treatment, brazing and pickling.