# UNS S15500 Forgings

15-5PH | ASTM A705/A705M Type XM-12 | AMS 5659 | W.Nr. 1.4545 | X5CrNiCu15-5

Source: https://www.steelforgepieces.com/Stainless-Steel/UNS-S15500.html
Manufacturer: Jiangyin Jiangnan Metal Co., Ltd., No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China. Tel +86 189 2135 9659. Email sales@steelforgepieces.com
Last reviewed: 2026-10-04

## Summary

UNS S15500 is the UNS number for 15-5PH, a martensitic precipitation-hardening chromium-nickel-copper stainless steel carrying about 15 % chromium, 5 % nickel and 2.5 to 4.5 % copper. It is solution annealed, then brought to strength by a single low-temperature ageing treatment between 482 and 621 degrees C. The alloy is the consumable-electrode remelted development of 17-4PH, with chromium held lower so that delta ferrite is suppressed, which gives steadier transverse properties in heavy sections.

Jiangyin Jiangnan Metal melts and forges UNS S15500 at one site in Jiangyin, Jiangsu, China, to ASTM A705/A705M Type XM-12 and AMS 5659, as open-die forgings and seamless rolled rings up to 6000 mm outside diameter and 30 tonnes single-piece weight.

## Designations

| System | Designation |
| --- | --- |
| UNS, United States | S15500 |
| ASTM type | XM-12 |
| Werkstoff-Nr., Germany | 1.4545 |
| EN name | X5CrNiCu15-5 |
| Trade and common names | 15-5PH, 15-5 PH, Alloy 15-5 |

S17400, 1.4542, X5CrNiCuNb16-4, AISI 630 and SUS 630 are not equivalents. Those designate 17-4PH.

## Specifications by product form

| Product form | Specification | Type or grade |
| --- | --- | --- |
| Forgings | ASTM A705 / A705M | XM-12 |
| Forgings, pressure equipment | ASME SA-705 | XM-12 |
| Bar and shapes | ASTM A564 / A564M | XM-12 |
| Sheet, strip, plate | ASTM A693 | XM-12 |
| Aerospace bar, forgings, rings | AMS 5659 | Type 1 vacuum melt, Type 2 ESR |
| Aerospace sheet, strip, plate | AMS 5862 | not applicable |
| Welding wire | AMS 5826 | not applicable |
| General requirements | ASTM A484 | not applicable |

ASTM B564 covers nickel alloy forgings and does not apply to S15500.

## Chemical composition, weight %

| Element | ASTM A705 / A564, XM-12 | AMS 5659 |
| --- | --- | --- |
| Carbon (C) | 0.07 max | 0.07 max |
| Manganese (Mn) | 1.00 max | 1.00 max |
| Silicon (Si) | 1.00 max | 1.00 max |
| Phosphorus (P) | 0.040 max | 0.030 max |
| Sulphur (S) | 0.030 max | 0.015 max |
| Chromium (Cr) | 14.00 to 15.50 | 14.00 to 15.50 |
| Nickel (Ni) | 3.50 to 5.50 | 3.50 to 5.50 |
| Copper (Cu) | 2.50 to 4.50 | 2.50 to 4.50 |
| Niobium + tantalum (Nb+Ta) | 0.15 to 0.45 | 0.15 to 0.45 |
| Molybdenum (Mo) | not specified | 0.50 max |
| Iron (Fe) | balance | balance |

AMS 5659 is the tighter document on residuals, holding sulphur to 0.015 % against 0.030 % in the ASTM grades, and it caps molybdenum where ASTM does not list the element.

## Heat treatment

| Condition | Temperature | Soak | Cooling |
| --- | --- | --- | --- |
| A, solution annealed | 1038 C / 1900 F | 0.5 h | Air |
| H900 | 482 C / 900 F | 1 h | Air |
| H925 | 496 C / 925 F | 4 h | Air |
| H1025 | 552 C / 1025 F | 4 h | Air |
| H1075 | 579 C / 1075 F | 4 h | Air |
| H1100 | 593 C / 1100 F | 4 h | Air |
| H1150 | 621 C / 1150 F | 4 h | Air |
| H1150M | 760 C / 1400 F then 621 C / 1150 F | 2 h + 4 h | Air after each |

H1000 and H1050 are not recognised conditions for this alloy. Where a drawing calls for one of them the intent is usually H925 or H1075. Annealing after hot work is at 1038 C for one hour with rapid cooling, so the material responds correctly to ageing.

## Minimum mechanical properties, bar and forgings

| Condition | Tensile min (MPa) | Tensile min (ksi) | Yield 0.2 % min (MPa) | Yield 0.2 % min (ksi) | Elongation min (%) | Reduction of area min (%) | Hardness (HB) |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Condition A | not specified | not specified | not specified | not specified | not specified | not specified | 363 max |
| H900 | 1310 | 190 | 1170 | 170 | 10 | 35 | 388 to 444 |
| H925 | 1170 | 170 | 1070 | 155 | 10 | 38 | 375 to 429 |
| H1025 | 1070 | 155 | 1000 | 145 | 12 | 45 | 331 to 401 |
| H1075 | 1000 | 145 | 860 | 125 | 13 | 45 | 311 to 375 |
| H1100 | 965 | 140 | 790 | 115 | 14 | 45 | 302 to 363 |
| H1150 | 930 | 135 | 725 | 105 | 16 | 50 | 277 to 352 |

These are specification minimums, not typical results. H1150M is supplied against properties agreed at enquiry, since the double-overaged values are not listed uniformly across the ASTM and AMS documents. Transverse properties are lower than longitudinal and cannot be determined where the section measures under about 76 mm in the test direction; rounds, squares and hexagons have no short-transverse direction. Properties of heavy forgings depend on section size and test location, so ruling section and sampling position are agreed at enquiry stage and testing is carried out on prolongations taken from the forging.

Charpy requirements, where the order carries them, are agreed as a separate line rather than taken from the grade tables. Impact testing to minus 60 C runs in the works laboratory; below that it is placed with an accredited laboratory.

## Physical properties

| Property | Metric | Imperial |
| --- | --- | --- |
| Density | 7.80 g/cm3 | 0.282 lb/in3 |
| Melting range | 1404 to 1440 C | 2560 to 2625 F |
| Modulus of elasticity | 196 GPa | 28.4 x 10^6 psi |
| Poisson's ratio | 0.27 to 0.30 | 0.27 to 0.30 |
| Thermal conductivity (150 C) | 17.8 W/m.K | 124 BTU.in/hr.ft2.F |
| Coefficient of thermal expansion | 10.4 um/m.C | 5.78 uin/in.F |
| Magnetic response | ferromagnetic in all conditions | ferromagnetic in all conditions |

Expansion and conductivity figures vary between published datasheets according to the temperature interval used.

## Melting and forging route

Steel is melted on site, not bought as billet. Carbon, alloy and stainless heats run through a 25 t electric arc furnace, are refined in 25 t and 50 t ladle furnaces and pass through 30 t or 60 t vacuum oxygen decarburisation where carbon and nitrogen need holding down. Maximum heat size is 60 tonnes.

S15500 is a remelted grade by definition. Protective-atmosphere electroslag remelting in 3 t and 6 t furnaces satisfies AMS 5659 Type 2. For Type 1 vacuum melt the route is 3 t vacuum induction melting followed by 6 t vacuum arc remelting. Both are in house, so the grade does not need subcontracting.

From ingot the part is cogged or upset on 6300 t, 4000 t or 2000 t hydraulic presses, or ring rolled on radial-axial mills at 6 m, 3 m and 1 m, with five hammers from 750 kg to 5 t for drawing out and smaller batches. Heat treatment follows in one of 14 furnaces, including two 15 m well-type furnaces for vertical quenching of long shafts. Machining, inspection and certification complete the route on the same site, so the certificate traces back to a melt number.

## Forged product forms

Seamless rolled rings, contoured rolled rings, forged rings, gear ring blanks, retaining rings, valve seat rings and slewing rings. Step shafts, pump and plunger shafts, eccentric shafts, crankshafts, spindles, rolls, rotors and tie rods. Flanges, tube sheets, discs, blocks, covers, hubs, nozzles, hollow bars, sleeves, bushings, cylinders, forged pipe and tube sections. Round, square, rectangular, flat and hex forged bar, and near-net contoured preforms. Valve stems, seat rings, bodies, bonnets, blocks, spools and manifolds.

## Working envelope

| Item | Limit | Set by |
| --- | --- | --- |
| Seamless rolled rings | OD 50 to 6000 mm | 6 m radial-axial ring mill; upset and punch below mill range |
| Forged shafts | to 14 000 mm turned length | C61160 horizontal lathe; 15 m well furnace for vertical quench |
| Discs, tube sheets, blocks | to 5000 mm machined diameter | 5000 mm vertical turning lathe |
| Bored cylinders, hollow shafts | to 1600 mm bore x 10 000 mm | CNC deep-hole drilling machine |
| Single-piece weight | to 30 000 kg | 60 t heat size; 6300 t press |

## Machining, welding and forming

S15500 cuts in every condition it can be supplied in, and H1150M gives the longest tool life. The usual sequence is to rough out in Condition A or an overaged condition, age to the required H condition, then finish machine. Fully aged H900 material at 388 to 444 HB is hard going for turning, drilling and milling.

Welding is by shielded fusion or resistance methods with AWS E/ER630 filler. Weldments should be re-solution treated and aged, or at minimum re-aged. The alloy is not suited to cold working and tolerates only mild forming, best in the overaged condition. Nitriding can be arranged through qualified treaters; case hardness and depth depend on the process and the ageing condition and are confirmed against the treater's qualified procedure.

## Applications

Chemical and plunger pump shafts, impeller and casing parts, compressor components. Valve stems, seat rings, bodies and blocks for ball, check, globe, gate and plug valves. Flanges, tube sheets, nozzles and covers for pressure vessels and shell-and-tube heat exchangers. Subsea and wellhead hardware including Christmas tree and BOP components. Gear blanks, spindles and turbine parts where transverse loading rules out an air-melted grade. Aircraft components, pressure transducer bodies and nuclear parts bought to AMS 5659. Forged rolls, wheels, manifolds and crankshafts in paper, sugar and cement plant.

## UNS S15500 compared with UNS S17400

| Attribute | UNS S15500 | UNS S17400 |
| --- | --- | --- |
| Common name | 15-5PH | 17-4PH |
| Werkstoff-Nr. | 1.4545 | 1.4542 |
| ASTM type or grade | XM-12 | 630 |
| Chromium | 14.00 to 15.50 % | 15.5 to 17.5 % approx. |
| Melt practice | consumable-electrode remelted, ESR or vacuum | commonly air melted |
| Delta ferrite | suppressed | present |
| Transverse toughness | higher | lower in the short-transverse direction |
| Heavy sections | more even properties | greater fall-off toward the centre |
| Forgeability | better under severe upsetting | more prone to splitting |
| Strength in matching H condition | comparable | comparable |

Published data does not agree on whether S15500 holds a real corrosion advantage over S17400. Both sit above 410 and below 304 and 316 in general corrosion resistance, so corrosion alone is a weak basis for choosing between them. The defensible reasons are section thickness, loading direction and whether the specification demands a remelted product.

## Inspection and certification

| Item | Detail |
| --- | --- |
| Chemical analysis | optical emission spectrometry to ASTM E415; carbon and sulphur by infrared to ASTM E1019; PMI by handheld analyser |
| Tensile | ASTM A370 or ISO 6892, on 600 kN and 300 kN machines |
| Impact | ASTM A370, to minus 60 C in house; below that through an accredited laboratory |
| Ultrasonic | ASTM A388, EN 10228-3 or SEP 1921, acceptance class as nominated |
| Magnetic particle, penetrant | ASTM E709 and ASTM E165 on request |
| Grain size | ASTM E112 |
| Class approvals | CCS, BV, DNV, LR, NK |
| Standard certificate | EN 10204 3.1 mill test certificate |
| Witnessed certificate | EN 10204 3.2, witnessed by BV, DNV, LR, SGS, TUV or the customer's own inspector |
| Marking | grade, heat number and length stamped on each piece |

Corrosion testing to ASTM A262, G28 or G48 is placed with an accredited laboratory and the report issued alongside the mill certificate. Flag it on the enquiry so it is scheduled before shipment.

## Supply terms

| Item | Detail |
| --- | --- |
| Minimum order | 10 kg, no minimum piece count |
| Lead time | 20 to 60 days; S15500 sits at the longer end because of the remelting step |
| Delivery condition | Condition A, or aged H900, H925, H1025, H1075, H1100, H1150, H1150M |
| Machining | as-forged, proof machined or finish machined to drawing |
| Pricing | quoted per enquiry against grade, drawing, delivery condition and quantity |
| Payment | 30 % advance by T/T with balance against shipping documents, or irrevocable L/C at sight |
| Drawing formats | PDF, DWG, DXF, STEP |

Six items in the first email usually remove a round trip: grade or specification, dimensions or drawing, quantity and expected repeat volume, delivery condition, heat treatment and testing requirements, then certification and destination port.

## Related pages

17-4PH: https://www.steelforgepieces.com/Stainless-Steel/17-4ph.html
PH13-8Mo: https://www.steelforgepieces.com/Stainless-Steel/PH13-8Mo.html
A286: https://www.steelforgepieces.com/Stainless-Steel/A286.html
All stainless grades: https://www.steelforgepieces.com/Stainless-Steel/
Carbon steel: https://www.steelforgepieces.com/Carbon-Steel/
Alloy steel: https://www.steelforgepieces.com/Alloy-Steel/
Tool steel: https://www.steelforgepieces.com/Tool-Steel/
Nickel alloy: https://www.steelforgepieces.com/Nickel-Alloy/

Technical data is compiled from AMS 5659, ASTM A705, ASTM A564 and published alloy datasheets including the ARMCO 15-5 PH product data bulletin and the Rolled Alloys 15-5 datasheet. It is given for guidance only and is not a warranty.