18Ni300 Maraging Steel (UNS K93120) - Ultra-High-Strength Alloy Supplier of Round Bars & Forgings | Shanghai Hangbo Alloy Group
Date: 2026年7月30日 Categories: News Views: 249
By Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier | ISO 9001:2015 | Est. 2012
Contact: sales@hangboalloy.com | WhatsApp (Lisa): +86 13611656360
Quick Answer: What Is 18Ni300?
18Ni300 (Maraging 300 / UNS K93120) is the highest-strength grade in the 18Ni maraging steel family, achieving a minimum tensile strength of 2000 MPa (300 ksi) through simple low-temperature aging. It provides 15-20% higher strength than 18Ni250 with adequate fracture toughness (KIC >=55 MPa root-m), making it ideal for rocket motor cases, high-performance gears, and specialty fasteners where maximum static strength is the primary design criterion. Shanghai Hangbo Alloy Group supplies 18Ni300 as round bars and forgings with AMS 6514 certification.
Key Properties
| Property | Value |
|---|---|
| UNS Number | K93120 |
| Density | 8.00 g/cm3 |
| Melting Range | ~1420-1440C |
| Max Service Temp. | ~400C |
| Tensile (Aged) | >= 2000 MPa (>= 300 ksi) |
| Yield (Aged) | >= 1930 MPa (>= 280 ksi) |
| Elongation (Aged) | >= 6% |
| Hardness (Aged) | 51-55 HRC |
| Fracture Toughness KIC | >= 55 MPa root-m |
| Key Standards | AMS 6514, ASTM A579 Gr.74 |
Product Overview
18Ni300 represents the maximum-strength point in the standard 18% Ni-Co-Mo-Ti maraging family. By increasing cobalt to 8.5-9.5% and titanium to 0.5-0.8% (vs. 7.0-8.5% Co and 0.3-0.5% Ti in 18Ni250), the alloy precipitates a higher volume fraction of nanometer-scale Ni3Mo and Ni3Ti particles during aging, pushing tensile strength past 2000 MPa.
The trade-off is fracture toughness: KIC >=55 MPa root-m (vs. >=80 for 18Ni250). 18Ni300 is chosen when strength density is prioritized over damage tolerance -- rocket motor cases that operate at high stress but see limited fatigue cycling, or tooling components that require maximum wear resistance.
Shanghai Hangbo Alloy Group supplies 18Ni300 as round bars and forgings, solution-annealed (soft, ~30 HRC) for customer machining and aging, or fully heat-treated to the 300 ksi condition.
Chemical Composition (wt.%)
| Element | Min | Max |
|---|---|---|
| Ni | 18.0 | 19.0 |
| Co | 8.5 | 9.5 |
| Mo | 4.6 | 5.2 |
| Ti | 0.50 | 0.80 |
| Al | 0.05 | 0.15 |
| C | - | 0.03 |
| Fe | Balance | - |
Mechanical Properties
| Condition | Tensile (MPa) | Yield (MPa) | Elongation (%) | Hardness (HRC) |
|---|---|---|---|---|
| Solution-Annealed | 950-1100 | 800-950 | 12-18 | 28-33 |
| Aged 480C/3h | >= 2000 | >= 1930 | >= 6 | 51-55 |
Heat Treatment
Solution Anneal: 815-830C/1h/air cool. Age: 480-500C/3-6h/air cool.
No oil or water quench -- air cooling produces fully martensitic structure for sections up to 100 mm. Aging contraction <0.1%, isotropic.
Applications
| Industry | Component |
|---|---|
| Rocket & Missile | Solid rocket motor cases, pressure vessels |
| Aerospace Tooling | High-pressure die-casting dies |
| Defense | Ordnance components, armor-piercing bodies |
| Racing | Transmission shafts, gears |
FAQ
Q1: 18Ni300 vs 18Ni250? 300 has 15-20% higher strength (2000 vs 1725 MPa) but lower fracture toughness (55 vs 80 MPa root-m). Choose 300 for maximum static strength; choose 250 for balanced strength + toughness.
Q2: Welding? Yes, GTAW with matching 18Ni filler. Post-weld age at 480C restores full strength.
Q3: Price? $35-60/kg EXW. Higher Co + Ti content vs 18Ni250. Contact sales@hangboalloy.com.
Q4: Rust? Yes, ~65% Fe. Requires plating, painting, or oil protection.
Q5: Shipping? FOB/CIF/DAP to 40+ countries. VIM+VAR lead time 12-16 weeks.
Contact Shanghai Hangbo Alloy Group
| Channel | Details |
|---|---|
| Company | Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier |
| Website | www.nickel-alloy.com |
| sales@hangboalloy.com | |
| WhatsApp (Lisa) | +86 13611656360 |
Shanghai Hangbo Alloy Group - Complete Product Range
| Family | Available Grades |
|---|---|
| Pure Nickel | NI200, NI201, N4, N5, N6 |
| Monel | Monel 400, 401, 404, K-500, R-405 |
| Inconel | Inconel 600, 601, 617, 625, 690, 718, X-750, 725 |
| Incoloy | Incoloy 800, 800H, 800HT, 825, 925, 926, A-286, 25-6HN |
| Hastelloy | C-276, C-22, C-2000, C-4, G-30, G-35, X, B-2, B-3, N |
| Nimonic | Nimonic 75, 80A, 90, 95, 105, 115, 263 |
| Haynes | Haynes 25, 188, 230, 242, 282, 556 |
| Precision | 1J22, 1J46, 1J50, 1J79, 1J85, 3J21, 4J32, 4J36, 4J45 |
| High-Strength | 18Ni250, 18Ni300, AerMet 100, PH13-8Mo |
| Specialty | Alloy 20, 59, 254SMO, RA330, Inconel 686, 602CA |
Product Forms
Bars (6-500mm) | Tubes (OD 6-610mm) | Plates (0.1-100mm) | Forgings | Welded Pipes | Fittings | Wire & Strip
SGS/BV/TUV inspection available. Contact sales@hangboalloy.com | www.nickel-alloy.com
