Stainless Steel 17-7 PH Round Bar
➡️ AISI 631 | UNS S17700 | EN 1.4568 | ASTM A564
➡️ ASTM, EN, JIS & International Standards
➡️ Supply Conditions
➡️ Multiple Diameters & Supply Lengths
➡️ Global Export & International Delivery
Country of Origin:
Europe, Japan, USA
Material Type:
Stainless Steel
UNS Number:
S17700
Wr. No.:
1.4568
MTC Available:
EN 10204 3.1
Product Description for Stainless Steel 17-7 PH Round Bar
Stainless Steel 17-7 PH Round Bar is sold as UNS S17700 and W.Nr. 1.4568. The bar standard is ASTM A564 / A564M (Type 631). Dimensional and surface requirements sit in ASTM A484 / A484M. EN, JIS, GB/T and KS all carry an equivalent designation.
The grade is a semi-austenitic precipitation-hardening stainless steel with 16-18% chromium, 6.5-7.75% nickel and 0.75-1.50% aluminium. In Condition A the structure is austenitic and readily formed; a conditioning treatment then transforms it to martensite, and a final ageing step precipitates nickel-aluminium compounds to produce tensile strength of at least 1280 MPa in the RH950 condition with good corrosion resistance.
The delivery condition is Condition A (annealed) or transformed and aged (TH1050 / RH950). Available finishes include hot finished and pickled, cold drawn, peeled, turned, centreless ground and polished, and the choice follows the tolerance and surface quality the part needs. Common diameters run 3 mm to 500 mm, larger on request by forging, in 3 to 6 m random lengths or cut to size. Strength is developed by a low-temperature precipitation-hardening (ageing) treatment carried out after machining.
It is machined into springs, retaining rings, diaphragms, fasteners and formed precision components. The main buyers are in aerospace, instrumentation, defence and precision mechanical engineering. Documentation is usually an EN 10204 3.1 certificate listing the heat analysis, the mechanical test results and the condition supplied. Density is around 7.81 g/cm3 and the modulus of elasticity about 200 GPa. Third party inspection, positive material identification and non-destructive examination can be added at order stage.
Common Applications of Stainless Steel 17-7 PH Round Bar
➡️ Machined shafts, spindles, valve stems, pump sleeves and pins for food, beverage, dairy and pharmaceutical equipment, where the passive chromium oxide film resists both product acids and caustic clean-in-place chemicals.
➡️ Fasteners, studs, bolts, threaded rod and anchor components produced from bar stock, chosen for corrosion resistance combined with the ductility needed for cold heading and thread rolling.
➡️ Chemical, water treatment and general process plant parts such as agitator shafts, flange blanks, nozzles and support components handling water, steam and mildly corrosive media free of significant chlorides.
➡️ Architectural and structural hardware including handrail stanchions, balustrade fittings, tension rods and bollards, where a bright ground or polished bar finish provides both appearance and low maintenance.
International Equivalent Grade for SS 17-7 PH Round Bar
Standard
Country / Region
Grade
ASTM A564 / A564M (Type 631)
USA
UNS S17700 - Type 631 (17-7 PH)
ASME SA-564
USA
UNS S17700 - Type 631 (17-7 PH)
EN 10088-3
Europe / EU
1.4568 (X7CrNiAl17-7)
BS EN 10088-3
United Kingdom
1.4568 (X7CrNiAl17-7)
JIS G4303
Japan
SUS631
GB/T 1220
China
07Cr17Ni7Al (S51770)
KS D 3706
South Korea
STS631
ISO 15510
International
X7CrNiAl17-7
Technical Specification for Stainless Steel 17-7 PH Round Bar
Specification
Value
Unit
Material
Stainless Steel
-
Grade
17-7 PH / UNS S17700 / W.Nr. 1.4568
-
Product Form
Round Bar / Rod
-
Standard
ASTM A564 / A564M (Type 631)
-
Diameter
3 - 500 (larger by forging on request)
mm
Length
3 - 6 (random mill length) or cut to length
m
Manufacturing Process
Hot rolled, forged or cold finished
-
Production Route
EAF + AOD / VOD refining, continuous cast or ingot, hot rolled or forged
-
Surface Finish
Hot-finished and pickled, cold-drawn, peeled, turned, ground or polished
-
Heat Treatment / Delivery Condition
Condition a (annealed) or transformed and aged (th1050 / rh950)
-
Tolerance Standard
ASTM A484 / A484M
-
Carbon Equivalent (CEV)
Not applicable (CEV applies to carbon and low-alloy steels)
-
Density
7.81 (nominal)
g/cm3
Melting Range
1400 - 1440 (typical)
C
Thermal Conductivity at 100 C
16.4 (typical)
W/m.K
Coefficient of Thermal Expansion (0-100 C)
11.6 (typical)
10-6/K
Specific Heat (0-100 C)
460 (typical)
J/kg.K
Electrical Resistivity at 20 C
0.83 (typical)
micro-ohm.m
Modulus of Elasticity at 20 C
200 (typical)
GPa
Magnetic Properties
Ferromagnetic in all conditions
-
Applicable Testing / Inspection Standard
ASTM A370 (mechanical testing), ASTM E18 / E10 (hardness)
-
Certification / Inspection Documents
EN 10204 3.1 mill test certificate standard, 3.2 third-party, PMI, ultrasonic and dye-penetrant examination available on request
-
Technical Specifications
Get the key technical specifications for Stainless Steel 17-7 PH Round Bar
Buyers specify ASTM A564 / A564M (Type 631) for the material and ASTM A484 / A484M for dimensions and surface. In Europe the same steel is called 1.4568 (X7CrNiAl17-7). The ordered standard and condition should appear on the order and on the certificate.
Hardening requires a multi-stage sequence. For TH1050 the material is conditioned at 760 C, cooled to 15 C and aged at 565 C. For RH950 it is conditioned at 955 C, refrigerated at -73 C and aged at 510 C, which gives the higher strength level.
Hot finished bar is rolled or forged, then heat treated and pickled. Cold finished bar is drawn, peeled, turned or ground after that. Diameter, out of round, straightness and length tolerances shift with size and finish class, so they are read from the dimensional standard or agreed case by case.
ASTM A564 notes that Type 631 contains a significant amount of ferrite and can show low ductility in forgings and larger-diameter bars, so applications are best limited to smaller sections. The multi-stage heat treatment is the practical distinction from 17-4 PH and 15-5 PH, which need only a single ageing step. In exchange, the grade can be formed extensively in the soft austenitic Condition A before hardening.
The physical properties quoted are typical mill values, not requirements of the standard. Testing is to ASTM A370, with results, analysis, condition and heat number on the certificate.
Chemical Composition for Stainless Steel 17-7 PH Round Bar
Element
Symbol
Min
Max
Unit
Carbon
C
-
0.09
%
Manganese
Mn
-
1.00
%
Silicon
Si
-
1.00
%
Phosphorus
P
-
0.040
%
Sulfur
S
-
0.030
%
Chromium
Cr
16.00
18.00
%
Nickel
Ni
6.50
7.75
%
Aluminium
Al
0.75
1.50
%
Chemical Composition
View the chemical composition and applicable material limits for SS 17-7 PH Round Bar
Aluminium at 0.75-1.50% is the precipitation hardener, forming NiAl during ageing. Nickel is deliberately held at 6.5-7.75%, low enough that austenite becomes unstable during conditioning and transforms to martensite on cooling.
Chromium runs 16.00 to 18.00% here, and it is what makes the steel stainless: it builds the passive oxide film that resists attack. Nickel at 6.50 to 7.75% stabilises the structure and improves ductility and toughness. The standard also fixes aluminium 0.75 to 1.50%. Carbon is capped at 0.09%.
The manganese and silicon come from deoxidation and add slight strength. Phosphorus and sulphur are residual elements with low ceilings, because they cost hot workability, weldability and corrosion resistance.
ASTM, EN, JIS, GB/T and KS versions of the grade set slightly different limits. For general work the gap rarely matters; for severe corrosion or hot service it can, so check the heat analysis on the certificate against the standard ordered. Chemical analysis is carried out to ASTM A751. Where the composition table shows no limit for an element, the standard sets no requirement and the element need not be determined or reported.
Mechanical Properties for Stainless Steel 17-7 PH Round Bar
Mechanical Property
Value
Unit
Hardness (Condition A, solution annealed)
229 (max) / 98 HRB (max)
HBW
Tensile Strength (RH950)
1280 (min)
MPa
Yield Strength 0.2% (RH950)
1030 (min)
MPa
Elongation in 50 mm (RH950)
6 (min)
%
Reduction of Area (RH950)
25 (min)
%
Hardness (RH950)
41 HRC / 388 HBW (min)
-
Tensile Strength (TH1050)
1170 (min)
MPa
Yield Strength 0.2% (TH1050)
965 (min)
MPa
Elongation in 50 mm (TH1050)
6 (min)
%
Reduction of Area (TH1050)
25 (min)
%
Hardness (TH1050)
38 HRC / 352 HBW (min)
-
Modulus of Elasticity
200 (typical)
GPa
Mechanical Properties
Check the key mechanical properties and performance requirements of SS 17-7 PH Round Bar
ASTM A564 specifies 1280 MPa minimum tensile strength, 1030 MPa minimum yield and 41 HRC for Type 631 in RH950, and 1170 MPa minimum tensile with 965 MPa yield and 38 HRC in TH1050. Elongation is limited to 6% minimum and reduction of area to 25% in both conditions, and Condition A hardness is capped at 229 HBW.
Everything depends on the ageing treatment applied after solution treatment. A low ageing temperature buys strength and hardness; a higher one trades them for toughness and resistance to stress corrosion cracking. Results are certified against the ordered condition, tested to ASTM A370 and ASTM E18.
Design to the minima of the ordered standard and condition; the certificate carries what the heat actually achieved. Bar diameter has an effect of its own, through cooling rate in heat treatment and the amount of working the section received.
This combination of very high strength with useful corrosion resistance and low distortion during hardening is why the grade is selected for highly loaded aerospace, subsea and rotating machinery components. Fatigue performance is good, but notch sensitivity rises with strength level, so higher ageing temperatures are often specified where impact or stress corrosion resistance matters more than peak strength.
Dimension / Sizes for Stainless Steel 17-7 PH Round Bar
Dimension / Size
Value
Unit
Diameter (standard supply range)
3 - 500 (larger by forging on request)
mm
Standard Length
3 - 6 (random mill length)
m
Custom Length
Cut to length available on request
-
Diameter Tolerance
Per ASTM A484 / A484M, varies with size and finish class
-
Length Tolerance
Per ASTM A484 / A484M or as agreed on the order
-
Straightness Tolerance
Per ASTM A484 / A484M or as agreed on the order
-
End Condition
Square cut, saw cut, chamfered or as ordered
-
Surface Finish
Hot-finished and pickled, cold-drawn, peeled, turned, ground or polished
-
Available Size Range (cold-finished bar)
3 - 100 (typical commercial capability)
mm
Available Size Range (hot-finished and forged bar)
16 - 500 (typical commercial capability)
mm
Cut-to-Length Availability
Available, tolerance to be agreed at order stage
-
Applicable Dimensional Standard
ASTM A484 / A484M
-
Dimensions & Sizes
Explore available diameters, lengths, and dimensional requirements for SS 17-7 PH Round Bar
Pricing for Stainless Steel 17-7 PH Round Bar
Round Bar Prices are generally quoted per kilograms or meters tonnes and can fluctuate with the global raw material and market prices. The final price will depend on a variety of factors, including the grade size, diameter, length, surface finish, the quantity and whether the bars are cut to length or in standard lengths.
For smaller quantities, we can also quote per metre or per piece basis once the required dimensions have been confirmed. Container-loads or orders that are larger in size are typically priced per tonne, based upon the specifications required and the supply conditions.
Please provide your desired dimensions, grades, length number, and end for a current quote including the lead time applicable and details for certification.
Pricing
Get current Stainless Steel 17-7 PH Round Bar pricing based on size, quantity, grade, finish, and delivery requirements.
Why Choose Us
Euro Steel Bars is an international distributor, stockist and exporter of stainless round steel bars that cover carbon, stainless alloy, special grades. We stock a variety of sizes and grades. We guarantee every order with mill test certificates as well as full quality-assurance documentation. Our name speaks to our roots: European-sourced materials that is backed by the certificates and rigor that buyers from Asia as well as the Gulf and Africa are looking for.
Each bar we deliver is accompanied by EN 10204 3.1 mill test certificates as well as complete documentation of quality, so what you receive corresponds to what’s written in the documents. We carry a selection of sizes and grades ready for transport, and cut length upon the request of customers, which results in quicker lead times, whether you’re ordering just a one-off spec or a complete project tonnage.
We operate an actual wholesale business that is that is supported with an internationally-operated supply chain therefore we are able to serve fabricators sourcing one grade the same way in the same way as an EPC contractor who is placing a large order. Our clients include manufacturers, fabricators EPC construction companies, engineers oil and gas projects as well as construction companies. we design our inventory as well as documentation to show what buyers need to bring projects forward.
Our customers trust us across Qatar, Oman, Bahrain, Kuwait, Jordan, Malaysia, Singapore, Thailand, Taiwan, Turkey, Italy and South Africa. If you’re looking to source an Gulf energy project, or a construction project within Southeast Asia, you get the same quality of certified material, the exact documentation, and the exact delivery procedure.
Frequently Asked Questions
What is Stainless Steel 17-7 PH Round Bar?
What standard does Stainless Steel 17-7 PH Round Bar comply with?
What are the equivalent grades of Stainless Steel 17-7 PH Round Bar?
What sizes and lengths are available in Stainless Steel 17-7 PH Round Bar?
What are the key mechanical properties of Stainless Steel 17-7 PH Round Bar?
What is the typical chemical composition of Stainless Steel 17-7 PH Round Bar?
Can Stainless Steel 17-7 PH Round Bar be supplied cut to length or with a specific surface finish?
What is the difference between TH1050 and RH950 conditions?
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