SS316 and 17-4 PH are common used two types of stainless steel grades for investment casting. 316 is typical austenite stainless steel casting grade, while 17-4 PH stainless steel is precipitation hardening material grade, which are all defined in American standards. When you compare Stainless Steel 17-4 ph vs 316 for casting, it is obvious that 17-4 PH has the higher hardening content. Precipitation hardening grade is actually a combination of two stainless steel structures such as austenite and martensite. Both 17-4 ph and 316 stainless steel castings offer high corrosion resistance.
CFS Foundry is the professional stainless steel casting company, we are able to cast both 17-4 PH and 316 stainless steels. These two types of stainless steel castings are used in different applications due to the differences of chemical compositions and mechanical properties. To check the differences between 17-4 PH and 316 stainless steel castings. We tested these two kinds of stainless steel casting samples in chemical lab and mechanical lab on different testing equipments. The chemical compositions of 17-4 PH stainless steel casting and 316 stainless steel casting are carried out to identify the chemical composition whereas the mechanical tests are performed to know the strength of 316 vs 17-4 samples.
After carefully testing and comparison, it can be clearly checked that chemical composition for the two grades are bit different in terms of molybdenum, copper, columbium and Tantalum etc. The summary of results is shared below:
| CHEMICAL COMPOSITION | ||
| GRADES >> | SS316 | 17-4PH |
| Carbon | 0.05 | 0.06 |
| Manganese | 2 | 0.9 |
| Phosphorous | 0.045 | 0.03 |
| Sulphur | 0.03 | 0.02 |
| Silicon | N/A | 0.9 |
| Copper, columbium and Tantalum | N/A | 4 |
| Molybdenum | 2.1 | N/A |
| Nickel | 8 | 4 |
| Chromium | 18 | 17.5 |
The mechanical properties of 17-4PH stainless steel casting is higher in terms of hardness, tensile strength and yield strength as compare to the sample of SS316 stainless steel casting. Here are the summary of results for mechanical properties below:
| MECHANICAL PROPERTIES & STRENGTH | ||
| GRADES >> | SS316 | 17-4PH |
| Tensile Strength Mpa | 545 | 1276 |
| Yield Strength Mpa | 275 | 1170 |
| Hardness (HB) | 220 | 350 |
| Elongation % | 50% | 8% |
Note: Before shipping, either 304 or PH 17-4 stainless steel casting, stainless steel casting manufacturer should test the chemical compositions and mechanical properties personally to prove if the testing results are within the required range. Only qualified stainless steel castings can be shipped to customers, and related testing reports should be provided together.