Project Description

 

Introduction

PH 13‑8 Mo is a precipitation‑hardening martensitic stainless steel designated as ASTM XM‑13, UNS S13800, and EN 1.4534. It offers a superior combination of high strength, excellent fracture toughness, and good resistance to stress corrosion cracking in chloride environments up to approximately 300 °C. The alloy is strengthened by precipitation of nano‑scale intermetallic phases during a single‑step ageing treatment, achieving tensile strengths above 1500 MPa while retaining ductility. Typical industries include aerospace, chemical processing, oil & gas, nuclear, and high‑performance engineering where high specific strength and corrosion resistance are critical. It is widely specified for critical fasteners, structural components, and valve parts in severe service conditions.

PH 13-8 Mo stainless steel product
PH 13‑8 Mo / XM‑13 Round Bar

Equivalent Grades & Standards

Standard / System Grade / Designation
ASTM XM‑13 per ASTM A564, A693, A705
AMS AMS 5629 (bar, wire, forgings), AMS 5864, AMS 5934
EN / DIN 1.4534 / X3CrNiMoAl 13‑8‑2 per EN 10088‑3
UNS S13800
JIS No direct equivalent; closest SUS 632 (0Cr13Ni8Mo2Al)
GOST No direct equivalent; closest 07Kh16N6

Typical Applications

Aerospace: structural brackets, wing‑to‑fuselage attachments, engine mounts, landing gear components, rocket motor casings.
Oil & Gas: subsea bolting, valve stems, pump shafts, christmas tree components, sour service fasteners.
Chemical Processing: agitator shafts, valve trim, heat exchanger internals, reactor vessel bolting.
Nuclear: control rod drive mechanisms, reactor internals, high‑strength bolting.
Medical: orthopaedic implants, surgical instruments requiring high static and fatigue strength.
Power Generation: turbine blades, compressor discs, high‑temperature fasteners.

Supply Range

Form Dimensions
Round Bar Dia. 8 mm – 350 mm (0.31″ – 14″)
Flat Bar Thk. 4–60 mm × W 15–300 mm
Plate / Sheet Thk. 0.5–60 mm × W up to 2000 mm
Seamless Tube OD 10–200 mm × WT 1.0–20 mm
Wire Dia. 0.5–10 mm (0.02″–0.39″)
Forgings OD up to 1800 mm; weight up to 4000 kg

Chemical Composition

Per ASTM A564 Grade XM‑13 (weight %):

C Mn Si P S Cr Ni Mo Al N Fe
≤0.05 ≤0.10 ≤0.10 ≤0.010 ≤0.008 12.25–13.25 7.50–8.50 2.00–2.50 0.90–1.35 ≤0.01 Bal.

Tight control of carbon and nitrogen ensures high toughness and consistent precipitation hardening response.

Mechanical Properties

Condition Tensile Strength (MPa) Yield Strength 0.2% (MPa) Elongation (%) Hardness (HRC)
Solution Annealed (Condition A) ≈ 1035 ≈ 790 ≥ 17 ~33
H950 (Age 510°C) ≥ 1520 ≥ 1410 ≥ 10 44–48
H1000 (Age 538°C) ≥ 1310 ≥ 1210 ≥ 12 39–43
H1050 (Age 566°C) ≥ 1170 ≥ 1070 ≥ 15 35–39

Solution annealing is performed at 927 °C ± 15 °C followed by oil or air cooling. Subsequent ageing at the designated temperature develops the unique precipitation‑strengthened structure. The alloy retains excellent toughness down to cryogenic temperatures and offers superior fatigue resistance compared to conventional martensitic stainless steels.