Ni-Resist
An austenitic high-nickel cast iron
Typical values for the temper in the title
Ni-Resist is a name for a family of austenitic cast irons with 18–37% nickel. High nickel makes the structure austenitic, as in stainless steel, giving resistance to corrosion (also in seawater), heat and thermal shock, and good ductility. There are flake-graphite types (ASTM A436) and spheroidal-graphite types (ASTM A439, D grades).
D-2 (18–22% nickel) is used for pumps, valves and marine parts, and is non-magnetic. D-5S (34–37% nickel and 5% silicon) resists oxidation and thermal shock at high temperature, and is used for turbocharger housings and exhaust manifolds.
Mechanical and physical properties
| Property | Value | Note |
|---|---|---|
| Tensile strength Rm | 370-420 MPa | |
| Yield strength Rp0.2 | 200-210 MPa | |
| Elongation A | 7-20% | |
| Hardness | 120-170 HB | |
| Modulus of elasticity E | 100 GPa | |
| Density ρ | 7.4 g/cm³ | |
| Machinability | 50% | relative rating in the site database |
Chemical composition (wt %)
| Element | Range | Role |
|---|---|---|
| Ni nickel | 18.0–22.0 (D-2); 34.0–37.0 (D-5S) | austenitic structure |
| Cr chromium | 1.75–2.75 (D-2) | corrosion resistance |
| Si silicon | 1.50–3.00 (D-2); 4.90–5.50 (D-5S) | hot oxidation resistance |
| C carbon | max 3.00 (D-2); max 2.30 (D-5S) | spheroidal graphite |
| Fe iron | balance |
Ranges per the ASTM A439 table (spheroidal types).
Grades and conditions
Ni-Resist is austenitic, so it is not hardened by heat treatment. Stabilizing or stress-relief treatments are sometimes performed.
| Grade / condition | Properties | When to choose it |
|---|---|---|
| D-2 (A439) | non-magnetic, corrosion resistant | pumps, valves, marine parts |
| D-5S (A439) | resists oxidation and thermal shock when hot | turbocharger housings and exhaust manifolds |
| Flake types (A436) | cheaper, less ductile | pumps and simple parts |
Applications
- Pumps and valves for corrosive fluids
- Marine parts
- Turbocharger housings (D-5S)
- Exhaust manifolds
- Non-magnetic parts
Fabrication
Machining
Reasonable, but the material work hardens somewhat, like austenitic stainless.
Welding
Possible under controlled conditions, with nickel electrodes.
Magnetism
Per ASTM A439, D-2 is not attracted to a magnet, which serves as a quick shop check.
Compared with similar materials
| Material | Rm / Rp0.2 | Welding | When it is the better choice |
|---|---|---|---|
| Ductile Iron | 414–825 / 276–621 MPa | Medium — Ni Rod | ordinary ductile iron: cheap, not corrosion resistant · material page |
| 316 / 316L | 485–620 / 170–310 MPa | Excellent — ER316L | stainless: more resistant, costlier to cast · material page |
| Invar 36 | 485 / 275 MPa | Good | iron-nickel with low expansion · material page |
Common mistakes
Using D-2 in a hot turbocharger housing
For high heat and thermal shock, D-5S is more suitable.
Confusing flake and spheroidal types
Spheroidal types are much more ductile. EN numbers differ: GJLA for flake, GJSA for spheroidal.
Expecting stainless performance in every environment
Resistance is good, but not equal to stainless in every condition.
Equivalents, standards and supply
| EN | EN-GJSA-XNiCr20-2 (D-2) |
|---|---|
| ASTM | A439 D-2 / D-5S |
| Standards | ASTM A436 / ASTM A439 / EN 13835 |
| Forms | casting |
| Producers | Durabar · Wescast |
Learn more
Values are typical and for comparison only. In cast iron, properties depend strongly on wall thickness and cooling rate in casting. For design, rely on the standard and test-bar results. Sources: ASTM A48, A536, A897, A532, A439 and EN 1561/1563/1564, producer data sheets, and the METAL HUB materials database.
Updated: October 31, 2026