Why investment casting
Burner, nozzle and instrumentation parts combine thin walls, internal passages and heat-resistant alloys that are difficult to fabricate any other way.
Components
- Burner parts
- Nozzles
- Valve trim
- Instrumentation housings
- Fasteners and clamps
Materials
Heat-resistant steels, Cr-Mo steels, stainless steels, nickel alloys.
Frequently used alloys
| Grade | Type | Standard |
|---|---|---|
| HK | 25Cr-20Ni heat-resistant steel HK40 | ASTM A297/A297M |
| GX40CrNiSi25-20 (1.4848) | 25Cr-20Ni heat-resistant steel | EN 10295 |
| CF8M | Mo-bearing austenitic stainless steel, cast 316 type 316 type | ASTM A351/A351M, A743/A743M |
| CW-6MC | Ni-Cr-Mo-Nb alloy, cast Alloy 625 type Inconel® 625 type | ASTM A494/A494M |
Typical requirements
Elevated temperature, thermal cycling and long service life; material certification to pressure-equipment rules where applicable.
- Oxidation and creep resistance
- Material certificate 3.1
- Dimensional stability at temperature
Related engineering topics
Melting and pouring
Induction melting in air and vacuum, charge materials, melt treatment, pouring temperature and pouring methods for steel, stainless and nickel-alloy investment castings.
Material testing
Verification of cast alloys: spectrometric chemical analysis, PMI, tensile, hardness and impact testing, metallography, ferrite measurement, corrosion tests and heat-treatment verification.
Surface finish
Surface texture of investment castings: Ra and Rz, typical as-cast, blasted, ground and machined conditions, how to specify surface requirements and visual acceptance standards.