The SGS-75 : Self-lubricating stainless superalloy
The SGS-75 alloy is a «stainless and self-lubricating» alloy. Based on nickel (75%) and chromium (for corrosion resistance), it also includes bismuth and tin which give it its self-lubricating properties, make it particularly resistant to seizing and allow it to be used in contact with stainless steels, without lubrication, with reduced operating clearances.
Standard designation:
ASTM A494M grade CY5SnBiM
Chemical composition (in %) :
| Ni | C | Cr | Mo | Si | Mn | Fe | Bi | Sn |
| Bal. | 0,05 | 13 | 3 | 0,05 | 1,5 | 2 | 4 | 4 |
Properties
Corrosion resistance
Due to its chemical composition, SGS-75 alloy has a corrosion resistance comparable to AISI 304 and AISI 316 stainless steels, so it can easily replace them.
| SGS-75 | AISI 304 | AISI 316 | |
| Nitric acid HNO3 100% at 20°C | < 0,05 mm/ year | < 0,05 mm/year | < 0,05 mm/year |
| Acetic acid CH3COOH 50% at 60°C | from 0,05 to 0,5 mm/ year |
< 0,05 mm/year | < 0,05 mm/year |
| Hydrazine N2H4 100% at 20°C | from 0,05 to 0,5 mm/ year |
< 0,05 mm/year | < 0,05 mm/year with Mo < 0,5 % |
| Sea water at 20°C | < 0,05 mm/ year | < 0,05 mm/year | < 0,05 mm/year |
Based on the inertia principle defi ned by the EC Regulation N°1935/2004, SGS-75 is suitable for many food, chemical and pharmaceutical applications. SEVA can provide SGS-75 inertia results in different media, at different exposure times and temperatures. These values allow our customers to evaluate the food suitability of their equipment under their operating conditions and according to the applicable requirements.
Tribological properties
Tribology is the science of contacts between two parts in relative motion. It is therefore concerned with friction, the wear it causes and lubrication.
The SGS-75 alloy is made of an austenitic matrix rich in nickel, chromium and molybdenum as well as a secondary phase rich in bismuth and tin which gives it particular tribological properties.
So that tribological properties ofSGS-75 be uniform, it is necessary tohave a homogeneous distribution of the bismuth-tin phase in the parts produced.
The coefficients of friction with 316L stainless steel are significantly improved by the use of SGS-75:
- Coefficient of friction stainless steel 316L against stainless steel 316 L = 0.9.
- Coefficient of friction SGS-75 against stainless steel 316 L = 0.5.
Seizure tests (performed according to ASTM G98, with several stainless steels and a maximum stress of 350 MPa) revealed no seizure with the SGS75.
| AISI 201 | AISI 304 | AISI 316 | SAE 17-4 PH | 20 Cr - 80 Ni | |
| SGS-75 | 350+ MPa | 350+ MPa | 350+ MPa | 350+ MPa | 350+ MPa |
| AISI 201 | 137 Mpa | 14 MPa | 14 MPa | 14 MPa | N.C. |
| AISI 304 | 14 MPa | 14 MPa | 14 MPa | N.C. | N.C. |
| AISI 316 | 14 MPa | 14 MPa | 14 MPa | N.C. | N.C. |
| SAE 17-4 PH | 14 MPa | N.C. | N.C. | 14 MPa | N.C. |
SGS-75 added value
SGS-75 alloy makes it possible to fight and significantly reduce all the causes of wear and degradation to which mechanisms operating in severe environments are subjected.
Resistance to corrosion and tribocorrosion
SGS-75 offers a resistance to «static» corrosion equivalent to that of AISI 316 L. Thanks to the self-lubrication phenomenon, it allows to fight effectively against these surface aggressions and thus to increase in a way the resistance to tribocorrosion.
Self-lubrication
The self-lubrication provided by the SGS-75 greatly reduces adhesive wear and the risk of seizing. This reduces the coefficient of friction and therefore improves efficiency without the need for a lubricant.
Extended lifetime of the product
The SGS-75 features optimize performance and life in mechanical functions where there is or may be contact between parts that must resist to corrosion, without any external lubrication.
Vers un nouveau Business Model
The 3 main economic benefits
Added value of the SGS-75 for your equipment
Type of produced parts
Lobe pump rotors and components for the food industry:
Range of standard round bars and bushings:
As-cast and machined pump pistons:
Bearings and gear for handling and/or conveying systems in hostile environments (nuclear applications):
