Type 630 (UNS S17400 ) 17 - 4 pH) (Condition A) Stainless Steel Round Bar

China Type 630 (UNS S17400 ) 17

Model NO.
630
Surface Treatment
Bright
Transport Package
Wooden Box
Specification
OD 6-300mm
Origin
China
Model NO.
630
Surface Treatment
Bright
Transport Package
Wooden Box
Specification
OD 6-300mm
Origin
China

17-4PH Stainless Steel

17-4 Precipitation Hardening also known as Type 630 is a chromium-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 degrees Fahrenheit (316 degrees Celsius).

General Properties

Alloy 17-4 PH is a precipitation hardening martensitic stainless steel with Cu and Nb/Cb additions. The grade combines high strength, hardness (up to 572°F / 300°C), and corrosion resistance.

Mechanical properties can be optimized with heat treatment. Very high yield strength up to 1100-1300 MPa (160-190 ksi) can be achieved.

The grade should not be used at temperatures above 572°F (300°C) or at very low temperatures. It has adequate resistance to atmospheric corrosion or in diluted acids or salts where its corrosion resistance is equivalent to Alloy 304 or 430.

 
ApplicationsStandards
  • Offshore (foils, helicopter deck platforms, etc.)
  • Food industry
  • Pulp and paper industry
  • Aerospace (turbine blades, etc.)
  • Mechanical components
  • Nuclear waste casks
  • ASTM A693 grade 630 (AMS 5604B) UNS S17400
  • EURONORM 1.4542 X5CrNiCuNb 16-4
  • AFNOR Z5 CNU 17-4PH
  • DIN 1.4542

Corrosion Resistance

Alloy 17-4 PH withstands corrosive attacks better than any of the standard hardenable stainless steels and is comparable to Alloy 304 in most media.

If there are potential risks of stress corrosion cracking, the higher aging temperatures then must be selected over 1022°F (550°C), preferably 1094°F (590°C). 1022°F (550°C) is the optimum tempering temperature in chloride media.

1094°F (590°C) is the optimum tempering temperature in H2S media.

The alloy is subject to crevice or pitting attack if exposed to stagnant seawater for any length of time.

It is corrosion resistant in some chemical, petroleum, paper, dairy and food processing industries (equivalent to 304L grade).

If you would like to know more about 17-4PH stainless steel then click 17-4PH Technical Data.

 

Introduction

Grade 630 stainless steels are martensitic stainless steels that are precipitation hardened to achieve excellent mechanical properties. These steel achieve high strength and hardness following heat treatment. The heat and corrosion resistance of grade 630 are similar to that of grade 304 steels. This grades is also commonly referred to as grade 17-4PH.

One of the key benefits of this grade is that it is available in solution treated conditions, at which they can be easily machined and age-hardened to attain high strength. The age treatment of grade 630 is carried out at low temperatures, to avoid significant distortion. Therefore, this grade is used for applications such as the manufacture of long shafts that do not require re-straightening after heat treatment.

 

Key Properties

The properties mentioned below pertain to commonly available grade 630 bar products in ASTM A564. The specifications may not be similar to other forms such as forgings and plates.

Composition

The compositional ranges of grade 630 stainless steels are displayed below:

Table 1. Composition ranges for grade 630 stainless steels

 
GradeCMnSiPSCrNiCuNb+Ta
630

min.

max

-

0.07

-

1

-

1

-

0.04

-

0.030

15

17.5

3

5

3

5

0.15

0.45

Mechanical Properties

The table below outlines the mechanical properties of grade 630 stainless steels:

Table 2. Mechanical properties of grade 630 stainless steels

 
ditionTensile Strength (MPa)Yield Strength 0.2% Proof (MPa)Elongation (% in 50mm)Hardness
Rockwell C (HR C)Brinell (HB)
Solution Treated1105 typ1000 typ15 typ38 max363 max
Condition 9001310 min1170 min10 min40 min388 min
Condition 1150930 min724 min16 min28 min277 min
 

Physical Properties

The physical properties of grade 630 stainless steels are given in the following table:

Table 3. Typical physical properties of grade 630 stainless steels

 
Mean Co-eff of Thermal Expansion (µm/m/°C)Thermal Conductivity
(W/m.K)
Specific Heat 0-100°C
(J/kg.K)
Elec Resistivity
(nΩ.m)
0-100°C0-315°C0-538°CAt 100°CAt 500°C
630775019710.811.6-18.422.7460800

Grade Specification Comparison

The typical grade specifications of 630 stainless steels are tabulated below:

able 4. Grade specifications for grade 630 stainless steels

Grade

UNS

No

Old BritishEuronorm

Swedish

SS

Japanese

JIS

BSEnNoName
630S17400--1.4542X5CrNiCuNb16-4-

SUS 630

Table 5. Possible alternative grades to 630 stainless steels

GradeReasons for choosing 17/4PH (630)
431431 Has higher toughness than 17/4PH. Better availability in some sizes.
416Free-machining martensitic stainless steel - better for repetition machining. Lower cost.
316Higher corrosion resistance of 316 to resist more severe environments, but with much lower strength than 17/4PH.
2205Much better corrosion resistance than 17/4PH, with a lower strength (but not as low as 316).
 

Corrosion Resistance

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Grade 630 stainless steels have good corrosion resistance in many environments. They exhibit improved resistance against stress corrosion cracking, if aged at 550°C or more. However, grade 630 steels are less resistant to solution treated Condition A, and hence these steels, even with considerable hardness, should not be used in this condition.

Heat Resistance

Grade 630 stainless steels have good resistance to oxidation. However, long-time exposure of grade 630 to temperatures of 370 to 480°C should be avoided, to prevent loss of toughness at ambient temperature. These grades should not be used at temperatures above age-hardening temperature, to avoid reduction of hardness and mechanical properties of the metal.

Heat Treatment

Solution treatment (Condition A) - Grade 630 stainless steels are heated at 1040°C for 0.5 h, then air-cooled to 30°C. Small sections of these grades can be oil quenched.

Hardening - Grade 630 stainless steels are age-hardened at low temperatures to achieve the required mechanical properties. During the process, superficial discoloration occurs followed by shrinkage at 0.10% for condition H1150, and 0.05% for condition H900.

The table below shows the typical mechanical properties of grade 630 steels after solution treatment and age hardening:

Table 6. Typical mechanical properties of grade 630 steels achieved after solution treating

Cond.HardeningTypical Hardness Rockwell CTensile Strength (MPa)
Temp (°C)Time (h)
AAnn-361100
H900482144-
H9254964421170-1320
H10255524381070-1220
H10755804361000-1150
H1100593435970-1120
H1150621433930-1080

Welding

Grade 630 stainless steels can be welded using all conventional methods, and they do not require pre-heating. Care should be taken in designing and welding of high strength steels to prevent weldment stresses.

Machining

Grade 630 stainless steels can be machined in their solution-treated condition. They have machining rates similar to that of grade 304 steels.

Applications

Some of the major applications of grade 630 stainless steels include:

  • Engine components
  • High strength and boat propeller shafts
  • Plastic moulding dies
  • Valves and gears
 Type 630 (UNS S17400 ) 17 - 4 pH) (Condition A) Stainless Steel Round BarType 630 (UNS S17400 ) 17 - 4 pH) (Condition A) Stainless Steel Round BarType 630 (UNS S17400 ) 17 - 4 pH) (Condition A) Stainless Steel Round BarType 630 (UNS S17400 ) 17 - 4 pH) (Condition A) Stainless Steel Round Bar