Printed from Kezuriba (kezuriba.net/en/materials/fc250/)
FC250
ISO K (cast iron)Cast iron (gray cast iron = flake graphite cast iron). Standard: JIS G 5501 (Grey iron castings) (JIS G 5501:1995).
🌐International equivalents
“Close” means composition or properties are not exactly the same. Before substituting, check the values in each standard.
| System | Designation | Number | Relation | Confidence |
|---|---|---|---|---|
| JIS | FC250 | JIS G 5501 (Grey iron castings) | — | |
| ASTM | A48 Class 35 | Close (approximate) | One source / reference[8] | |
| EN | EN-GJL-250EN 1561 | Close (approximate) | One source / reference[8] | |
| SAE | J431 G3500 | Close (approximate) | One source / reference[8] | |
| GB | — | — | Not confirmed |
Differences between the equivalents (from the sources)
- ASTM A48 Class 35: In the cross-reference table of Goldens' Foundry (a US foundry), it is in the same row as FC250 (the table heading says "approximate"). Class 35 is the row with a tensile strength of 36,500 psi (about 252 MPa). Some sources match FC250 to Class 40, so this is not consistent
- EN EN-GJL-250: In the same row of the same Goldens' Foundry table. The old DIN designation is GG-25
- GB : Often given as HT250 (GB/T 9439), but not confirmed in primary sources
📄Related specifications (AMS, ASTM etc.)
Specifications called up on purchase orders and drawings. AMS are SAE aerospace material specifications, split by product form (bar, plate, forging), melting practice and heat treatment. Standard texts are paid, so only titles and scopes checked on the publishers’ public pages are shown.
| Spec | Scope | Confidence |
|---|---|---|
| ASTM A48/A48M-22 (Class 35) | Standard Specification for Gray Iron CastingsGray iron castings. Classified by the minimum tensile strength of separately cast test bars (Class 35 = 35,000 psi min). There are four test bar types by wall thickness: S, A, B and C | One source / reference[10] |
All ASTM standards on Kezuriba: ASTM standards quick reference.
⚗Chemical composition (mass %)
As specified in JIS G 5501
| Element | Range | Confidence |
|---|---|---|
| Chemical composition | JIS does not specify chemical composition and instead specifies mechanical properties (tensile strength and hardness of separately cast test bars). Showa Seisakusho explains that "chemical composition other than carbon is not specified by JIS". ASTM A48 likewise makes composition subordinate to tensile strength | One source / reference[4] |
⚖Density
—
Not confirmed
JIS has no density requirement, and no primary source giving the density of FC250 was found
The density could not be confirmed. In the weight calculator, use “Steel, general value” or enter your own.
💪Mechanical properties
“Reference” values are not specified minimums from the standard but figures published by makers and others.
| Condition | Tensile MPa | Yield MPa | Elong. % | Hardness | Type of value |
|---|---|---|---|---|---|
| Separately cast test bar (test piece taken from a 30 mm diameter test bar) | ≥ 250 | Not specified | Not specified | HB 241 max | JIS specified value (separately cast test bar) Agrees in 2+ sources[2][1][3][4] |
| Casting body (by wall thickness class) | — | — | — | — | JIS specified value (casting body) Not confirmed |
1 MPa ≈ 145 psi (0.145 ksi). Hardness conversion · unit converter
🔧Machinability notes (as stated in the sources)
- Sandvik Coromant: Gray cast iron (GCI) is ISO K. Chips break into short pieces and chip control is good under most conditions. Cutting forces are low and machinability is excellent. The hardness of GCI is about 180–245 HB[5]
- Sumitomo Electric recommended cutting conditions (turning): for gray cast iron (FC250, etc.), continuous to general cutting with AC4010K at vc 200–400–700 m/min; interrupted cutting with AC4015K at 180–300–450; heavy interrupted cutting with AC4125K at 150–200–300. High-speed finishing with CBN (BN7125) at vc 500–1,500–2,000 m/min[7]
- Sumitomo Electric evaluation example: continuous cutting of FC250 at vc = 600 m/min, f = 0.4 mm/rev, ap = 2.0 mm, dry[9]
- Showa Seisakusho: There is no notable difference in machinability between FC200 and FC250. Being brittle, the material can chip during cutting. Swarf can accumulate in the machine or mix with cutting fluid and cause clogging[4]
📚Sources
Primary sources (public documents from makers, industry associations and standards bodies), numbered where each value is cited. Many are in Japanese.
- marusank.jp https://marusank.jp/techinfo/column27/
- fukuchu.co.jp http://www.fukuchu.co.jp/product-standard.html
- horkos.co.jp https://www.horkos.co.jp/product/cas/tech01.php
- showa-ss.jp https://showa-ss.jp/fc200-fc250/
- sandvik.coromant.com https://www.sandvik.coromant.com/en-us/knowledge/materials/workpiece-materials
- kyocera.co.jp https://www.kyocera.co.jp/prdct/tool/wp-content/uploads/2014/07/2024-2026_A.pdf#page=8
- sumitool.com https://www.sumitool.com/downloads/cutting-tools/general-catalog/assets/pdf/a.pdf#page=16
- gfmco.com https://gfmco.com/wp-content/uploads/2021/07/Goldens-Guide-3-Ductile-Iron-Grades.pdf
- sumitool.com https://www.sumitool.com/downloads/cutting-tools/general-catalog/assets/pdf/a.pdf#page=17
- store.astm.org https://store.astm.org/a0048_a0048m-22.html
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