Stainless steel is popular in many industries because of its strength, durability, and corrosion resistance. One particular type worth knowing about is the 630 stainless steel. It is primarily used in the aerospace, chemical processing, and automotive industries. But what is this type of stainless steel, and what makes it stand out among other grades? This blog post will explore the composition, mechanical and physical properties, uses, corrosion resistance, heat treatments, and machining and welding considerations of 630 stainless steel.
Table of Contents
What is 630 Stainless Steel?
630 stainless steel, also known as 17-4 PH or 17-4 Precipitation Hardening steel, is a martensitic stainless steel containing approximately 15–17% chromium and 3–5% nickel. Due to its precipitation-hardening characteristics, it has excellent corrosion resistance and superior strength at high hardening depths. It can be used in applications requiring good mechanical properties at elevated temperatures up to 600°F (316°C).
630 Stainless Steel Composition
630 stainless steel, also known as 17-4PH or 630 Martensitic Stainless Steel, boasts of chromium, nickel, and copper constitutions, with little molybdenum and niobium. The unique composition of this stainless steel gives it excellent strength and toughness, which makes it highly desirable in the industries mentioned earlier. Specifically, the copper and nickel in the steel give it superior toughness, while the chromium content provides excellent corrosion resistance properties.
|
Grade |
C |
Mn |
Si |
P |
S |
Cr |
Ni |
Cu |
Nb+Ta |
|
|
630 |
min. max |
– 0.07 |
– 1 |
– 1 |
– 0.04 |
– 0.030 |
15 17.5 |
3 5 |
3 5 |
0.15 0.45 |
630 Stainless Steel Physical Properties
|
Grade |
Density |
Elastic Modulus |
Mean Co-eff of Thermal Expansion (µm/m/°C) |
Thermal Conductivity |
Specific Heat 0-100°C |
Elec Resistivity |
|||
|
0-100°C |
0-315°C |
0-538°C |
At 100°C |
At 500°C |
|||||
|
630 |
7750 |
197 |
10.8 |
11.6 |
– |
18.4 |
22.7 |
460 |
800 |
630 Stainless Steel Mechanical Properties
Mechanically, 630 stainless steel exhibits several characteristics that make it stand out among other stainless steel grades. This steel is highly resistant to stress corrosion and crevice corrosion. The alloy’s presence of copper and nickel makes it highly resistant to general corrosion. As for its physical properties, 630 stainless steel has a density of 7.75g/cm3, a melting point of 1370 – 1420℃, and a specific heat capacity of 480 J/kgK.
|
Condition |
Tensile Strength (MPa) |
Yield Strength 0.2% Proof (MPa) |
Elongation (% in 50mm) |
Hardness |
|
|
Rockwell C (HR C) |
Brinell (HB) |
||||
|
Solution Treated |
1105 typ |
1000 typ |
15 typ |
38 max |
363 max |
|
Condition 900 |
1310 min |
1170 min |
10 min |
40 min |
388 min |
|
Condition 1150 |
930 min |
724 min |
16 min |
28 min |
277 min |
630 Stainless Steel Specifications
|
Grade |
UNS No |
Old British |
Euronorm |
Swedish SS |
Japanese JIS |
||
|
BS |
En |
No |
Name |
||||
|
630 |
S17400 |
– |
– |
1.4542 |
X5CrNiCuNb16-4 |
– |
SUS 630 |
630 Stainless Steel Uses
Its high strength and superior mechanical and physical properties make it ideal for applications that require high strength, toughness, and corrosion resistance alongside high-temperature resistance. It finds its application in aerospace, chemical processing, power generation, and automotive industries. In the automotive industry, 630 stainless steel is commonly used for engine parts, transmission gearboxes, and hydraulic lines.
630 Stainless Steel Corrosion Resistance
Regarding corrosion resistance, 630 stainless steel is highly corrosion-resistant, thanks to its high chromium and copper content. Nevertheless, its corrosion resistance properties are enhanced when heat-treated using the appropriate heat treatment process. Speaking of heat treatments like quenching, tempering, and annealing all have different effects on the properties of 630 stainless steel.
630 Stainless Steel Machining
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As for machining and welding considerations, 630 stainless steel can be challenging to machine and weld adequately. This is a result of the steel hardening during the machining process. However, this can be mitigated using special techniques like proper coolant or lubrication, slow speeds, and sharp tools.
630 Stainless Steel Welding
On the other hand, welding 630 stainless steel requires preheating and post-weld heat treatment to prevent cracking and maintain its mechanical and physical properties.
Conclusion:
In conclusion, the properties of 630 stainless steel make it an ideal material for high-strength applications. Its copper, nickel, chromium, and molybdenum content gives it superior mechanical and physical properties and impressive corrosion resistance, toughness, and strength. That said, it is up to manufacturers and industries to utilize 630 stainless steel to its fullest potential, considering heat treatments, machining, and welding considerations. By doing so, they can reap the benefits of this type of stainless steel.
Grade 630 are stainless steels categorized as martensitic, but additionally this grade is precipitation hardened to attain robust mechanical properties. These steel acquire high tensile strength and resistance to indentation just after heat treatment. Resistance to corrosion and heat is comparable equivalent to that of grade 304 steels. This grade is also named as grade 17-4PH.
One of the main advantages of this grade is that it is marketed in conditions such as solution treated, at which they can be swiftly age-hardened (to gain high strength) and machined. The treatment to aging of grade 630 is implemented at low temperatures, to prevent considerable distortion. Hence this grade is employed for applications for instance the production of shafts (extended) after heat treatment that do not need re-straightening.
What is JIS G4303? It is a material standard produced by Japanese Standards Association on standardization and Specification of hot worked stainless steel bars with diverse forms and shapes.
Why SUS 630 called Grade 630 Stainless Steel? When a material grade is designated as SUS grade steel, it refers it is a Japanese name. SUS 630 is also called as Grade 630 steel in various international standards. It is explained in JIS G4303. Both grades have the same chemical composition and mechanical properties.
SUS 630 grade has got a high resistance to stainless steel as compare to SUS 304 Stainless Steel Austenite Grades. They show advance resistance to stress corrosion cracking, if aged at five hundred and fifty degree Celsius or more. But, SUS 630 steels offer reduced resistant to Condition A solution treated, and therefore these steels, also with significant hardness, should not be utilized in this condition A.
Available Forms in Market: Following are the available forms of SUS630 steels in the international market:
Bar Finish
Plates
Seamless Pipe
Welded Pipe
Pipe Fittings
Wire
Sheet
Forging
Dimensional Characteristics of SUS 630 Steels: Different suppliers supply with different specification ranges as per the demanded form. However commonly the thickness for this SUS 630 material as obtained by data in the market which starts from 1 mm to 30 mm. However the width of this material ranges to 700 mm to 1500 mm.
The Chemical Composition of SUS630 Steels: The chemical composition of this grade is as under:
Maximum percentage of Carbon (C) is 0.07 percent.
Chromium percentage ranges from 15 to 17%.
Maximum percentage of Manganese (Mn) is 1.0 percent.
Maximum percentage of Phosphorous (P) is 0.04 percent.
Maximum percentage of Sulphur (S) is 0.03 percent.
Maximum percentage of Silicon (Si) is 1.0 percent.
Minimum percentage of Nickel (Ni) is 0 percent and maximum is 5.0 percent.
Copper (Cu) ranges from 3 to 5 %.
Niobium (Nb) ranges from 0.15 to 0.45%
Remaining is iron (Fe) percentage and with few negligible impurities.
Mechanical Properties of SUS630 Steels: Following are some of the mechanical properties of 420 steels:
The tensile strength of the 630 alloy steel is expressed in Newton per millimeters and it must be at-least 930 N/mm2 (MPa) and maximum is 1310 N/mm2 (MPa).
The elongation property of SUS630 steel varies with the thickness and ranges from 40 to 50 %.
The minimum hardness range for this type is 277 HB.
Equivalent Material Grades in Other International Standards:
Equivalent grade of this type in American Standard is Grade 630 steel.
In DIN standard, the equivalent material is referred as 1.4542 type steel.
In UNS standard, the equivalent material is referred as S17400 type steel.
Applications of SUS630 Stainless Steels: Applications are as under:
Parts of Engine
Gears and Valves
Dies of plastic moulds
Waste bucket of Nuclear plant
Production equipment in aerospace such as turbine
Handling equipment used in offshore platform
Instruments in paper industry.
XTJ is a leading OEM Manufacturer that is dedicated to providing one-stop manufacturing solutions of Machining 6061 Aluminum from prototype to production. We are proud to be an ISO 9001 certified system quality management company and we are determined to create value in every customer relationship. We do that through collaboration, innovation, process improvements, and exceptional workmanship.lication: Automotive industry, Bicycle and motorcycle, Door and windows and furniture, Household appliance, Gas meter, Power tool,LED lighting, Medical instrument parts, ect.