CA 104 vs C52100 vs 9Cr18: Which Material Is Right for Your Application?
At FULLERKREG, we supply precision fasteners and engineered components across a broad range of specialty materials. CA 104 Aluminum Bronze, C52100 Phosphor Bronze, and 9Cr18 Martensitic Stainless Steel are three distinct materials frequently specified for bearing, spring, wear-resistant, and corrosion-resistant applications — each with a unique combination of strength, hardness, and environmental resistance.
This guide provides a direct technical comparison of all three grades per their respective standards, covering chemical composition and mechanical properties by size to support your material selection decision.
Alloy Overview
- CA 104 Aluminum Bronze (BS 2874:1986) — A high-strength copper-aluminum alloy with manganese, nickel, iron, and silicon additions. Excellent resistance to seawater corrosion, wear, and cavitation erosion. Non-sparking and non-magnetic. Governed by BS 2874:1986 CA 104.
- C52100 Phosphor Bronze (ASTM B139) — A copper-tin-phosphorus alloy in H04 (hard) condition. Outstanding spring properties, fatigue resistance, and corrosion resistance in aqueous environments. Widely used for springs, connectors, and bearing bushings. Governed by ASTM B139 C52100.
- 9Cr18 Martensitic Stainless Steel (GB/T 1220) — A high-carbon, high-chromium martensitic stainless steel with excellent hardness and wear resistance after heat treatment. Used for precision bearings, cutting tools, and corrosion-resistant wear components. Governed by GB/T 1220 9Cr18.
Chemical Composition Comparison
All values are weight percent (%). Min = minimum required; Max = maximum allowed per respective standard.
CA 104 Aluminum Bronze — BS 2874:1986
| Cu | Sn | Pb | Fe | Al | Mn | Ni | Si | Zn | Other Elements | |
|---|---|---|---|---|---|---|---|---|---|---|
| Min | Rem. | — | — | 4.0 | 8.5 | — | 4.0 | — | — | — |
| Max | — | 0.10 | 0.05 | 5.5 | 11.0 | 0.5 | 5.5 | 0.2 | 0.40 | 0.5 (excl. Mn) |
C52100 Phosphor Bronze — ASTM B139 (Condition H04)
| P | Cu | Fe | Pb | Sn | Zn | Condition | |
|---|---|---|---|---|---|---|---|
| Min | 0.03 | Rem. | — | — | 7.0 | — | H04 |
| Max | 0.35 | — | 0.10 | 0.05 | 9.0 | 0.20 |
9Cr18 Martensitic Stainless Steel — GB/T 1220
| C | Mn | P | S | Si | Cr | Ni | Mo | N | Cu | |
|---|---|---|---|---|---|---|---|---|---|---|
| Min | 0.90 | — | — | — | — | 17.00 | — | — | — | — |
| Max | 1.00 | 0.80 | 0.040 | 0.030 | 0.80 | 19.00 | 0.60 | — | — | — |
Mechanical Properties Comparison
CA 104 Aluminum Bronze — Mechanical Properties by Bar Size
| Bar Size (mm) | Tensile Strength Rm (N/mm²) min | Yield Strength Rp0.2 (N/mm²) min | Elongation A (%) min |
|---|---|---|---|
| <6 mm | ≥700 | ≥400 | ≥10 |
| 6–18 mm | ≥700 | ≥370 | ≥12 |
| 18–80 mm | ≥650 | ≥320 | ≥12 |
| >80 mm | ≥650 | ≥320 | ≥12 |
C52100 Phosphor Bronze — Mechanical Properties by Bar Size (H04 Condition)
| Bar Diameter | Tensile Strength Rm (N/mm²) | Yield Strength Rp0.2 (N/mm²) | Elongation A (%) min |
|---|---|---|---|
| ≤1/4″ (6 mm) | 720–1030 | — | — |
| 1/4″–1/2″ (6–12 mm) | ≥585 | — | ≥12 |
| 1/2″–1″ (12–25 mm) | ≥515 | — | ≥15 |
| >1″ (25 mm) | ≥415 | — | ≥20 |
9Cr18 Martensitic Stainless Steel — Mechanical Properties (Annealed)
| Hardness HB (max) | Yield Strength Rp0.2 | Elongation A (%) |
|---|---|---|
| ≤187 | — (annealed; hardness is the primary delivery condition) | — |
Note: 9Cr18 is typically supplied in annealed condition (HB ≤187) for subsequent hardening and tempering by the end user. After quench and temper, hardness typically reaches HRC 58–62, making it suitable for precision bearing and cutting tool applications.
Key Differences at a Glance
| Parameter | CA 104 Aluminum Bronze | C52100 Phosphor Bronze | 9Cr18 Martensitic Stainless |
|---|---|---|---|
| Alloy family | Cu-Al-Ni-Fe-Mn | Cu-Sn-P | Fe-Cr-C (martensitic) |
| Governing standard | BS 2874:1986 CA 104 | ASTM B139 C52100 | GB/T 1220 9Cr18 |
| Delivery condition | As-extruded / drawn | H04 (hard) | Annealed (HB ≤187) |
| Tensile Strength (N/mm²) | 650–700 (by size) | 415–1030 (by size) | Per heat treatment |
| Hardness after HT | ~200 HB | ~200 HB (H04) | HRC 58–62 (Q+T) |
| Corrosion resistance | Excellent (seawater, cavitation) | Good (aqueous, mild acids) | Good (dry/mild; not for chlorides) |
| Wear resistance | Excellent | Good | Outstanding (high hardness) |
| Non-sparking | Yes | Yes | No |
| Non-magnetic | Yes | Yes | No (ferromagnetic) |
| Primary applications | Marine hardware, bearings, pump components | Springs, connectors, bearing bushings | Precision bearings, cutting tools, wear parts |
Application Selection Guide
Choose CA 104 Aluminum Bronze when:
- High strength combined with excellent seawater corrosion and cavitation erosion resistance is required
- Non-sparking and non-magnetic properties are needed in marine or hazardous environments
- Wear resistance under heavy loads is a design criterion (e.g., bearing bushings, pump impellers)
- Typical applications: marine propeller shafts, pump casings and impellers, valve bodies, offshore platform hardware, naval vessel components, heavy-duty bearing bushings
Choose C52100 Phosphor Bronze when:
- Excellent spring properties, fatigue resistance, and electrical conductivity are required simultaneously
- Good corrosion resistance in aqueous and mildly acidic environments is needed
- The H04 hard condition provides the required strength without heat treatment
- Typical applications: precision springs, electrical connectors and contacts, bearing bushings, washers, snap rings, diaphragms, and instrument components
Choose 9Cr18 Martensitic Stainless Steel when:
- Maximum hardness and wear resistance after quench and temper are the primary requirements
- Moderate corrosion resistance in dry or mildly corrosive (non-chloride) environments is acceptable
- Precision bearing or cutting tool applications require a stainless-grade steel with HRC 58–62
- Typical applications: precision ball and roller bearings, surgical instruments, cutlery blades, measuring tools, corrosion-resistant wear plates, and high-hardness fasteners in dry environments
FULLERKREG Supply Capabilities
FULLERKREG supplies precision fasteners and engineered components in CA 104, C52100, and 9Cr18:
- Material Test Certificates (MTC) — EN 10204 3.1 / 3.2 available on request
- BS 2874 / ASTM B139 / GB/T 1220 compliance — rod and bar forms for fastener and structural applications
- 9Cr18 in annealed or hardened & tempered condition — per customer specification
- CA 104 non-sparking fasteners — for ATEX and marine hazardous area applications
- Bulk wholesale pricing — OEM and MRO procurement with competitive lead times
- Global shipping — from our manufacturing base in China to customers worldwide
Need a quote or technical consultation for CA 104, C52100, or 9Cr18 components? Contact FULLERKREG with your specification and our engineering team will respond promptly.
FULLERKREG — Precision Fasteners. Global Standards. Reliable Supply.