Martensitic precipitation Hardening stainless steel 17-4PH, SUS630 / S17400 thick wall thickness forged tube

1 PRODUCT

Martensitic precipitation hardened stainless steel 17-4PH (condition H1100, H1150 etc), SUS630, S17400 thick wall thickness forged seamless tube

2 EQUIVALENT DESIGNATION

0Cr17Ni4Cu4Nb(GB/T), AISI630(ASTM), W.Nr. 1.4542, X5CrNiCuNb16-4(DIN)

3 APPLICATION

(1) Oil-gas

(2) Petro-chemical

4 OVERVIEW

17-4PH is a chromium-nickel-copper precipitation hardening martensitic stainless steel used for applications requiring high strength and hardness along with a moderate level of corrosion resistance. High strength is maintained to approximately 600℉ (316℃). This alloy is designated Grade or Type 630 in several specifications.

17-4PH 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 alloy requires a simple heat treatment; a one step process conducted at a temperature in the range 900℉ (482℃) to 1150℉(621℃) 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℉ (482℃) range produces highest strength, although slightly less than that of alloys like S17700 or S15700. The latter precipitation hardening stainless steels generally require more steps to complete heat treatment.

5 CHEMICAL COMPOSITION (wt%):

6 PHYSICAL CONSTANTS

Density: 7.86 g/cm³ (0.284 lb/in³)

Melting point:1400-1440℃

7 MECHANICAL PROPERTY

Room temperature tensile properties can vary substantially with heat treatment in the 900℉(482℃) to 1150℉(621℃) range. Values shown below are typical room temperature properties that may be expected for various precipitation hardening heat treatments as well as for the 1950℉(1066℃) solution heat treatment.

8 CORROSION RESISTANCE

17-4PH has superior corrosion resistance to any other standard hardened stainless steel.

Tests have shown that the corrosion resistance of 17-4PH is comparable to that of Type 304 stainless steel in most media. In general, the corrosion resistance of 17-4PH alloy is superior to that of the hardenable 400 series stainless steels. As with other precipitation hardening stainless steels, 17-4PH is more susceptible to stress corrosion cracking at peak strength. Consequently, in applications where chloride stress corrosion cracking is a possibility, the material should be precipitation hardened to produce the lowest hardness compatible with the intended end use. This is done by heat treating at the highest temperature which will produce suitable minimum properties.

Material in the annealed condition should not generally be put into service. In this condition, the material has an untempered martensite structure and is less ductile than aged material. The untempered martensite may be subject to unpredictable brittle fractures. In corrosive environments, the untempered martensite is more sensitive to embrittling phenomena such as hydrogen embrittlement than material that has had one of the precipitation hardening heat treatments. Similarly, untempered martensite is more sensitive to chloride stress corrosion cracking than material in which the martensite has been tempered.

This alloy is susceptible to corrosion or crack corrosion in static seawater.

It has the same resistance to corrosion in the petrochemicalm, food processing and paper industry as the 304L grade.

9 OXIDATION RESISTANCE

The oxidation resistance of the 17-4PH is superior to that of 12 percent chromium alloys like Type 410, but slightly inferior to that of Type 430. Precipitation hardening will produce surface oxidation.

10 HEAT TREATMENT

The 17-4PH is furnished in the annealed condition. This is also called the solution heat treated condition, or Condition A. Annealing is conducted by heat treating at approximately 1900℉ (1040℃) to 1950℉ (1065℃) and cooling to room temperature. In this condition, the material possesses a martensitic structure. As a martensitic structure, the 17-4PH alloy possesses a relatively high strength and hardness in the annealed condition. The strength and hardness of the material is generally somewhat lower in the H1150 over aged condition.

The heat treatments used for the 17-4PH precipitation hardening stainless steel are summarized below.

11 PROCESS

Forging → Rough machining → Solution annealing → Aging → Center hole boring → Test & Inspection

12 PRODUCT CAPACITY

OD: 120-300 mm

ID: 50-200 mm

Length: 500-10,000mm

Straightness: ≤1mm/m

Surface: rough machined

13 STANDARD SPECIFICATION

SAE AMS 5643R

ASTM A564

14 BUSINESS TERM