Alloy & tool steel
MO40 steel (1.7225 / 42CrMo4)
Chromium-molybdenum steel for quenching and tempering: highly stressed shafts, axles and bolts; round, forged flat and plate.
MO40 is the Iranian market name of 42CrMo4, material number 1.7225: a chromium-molybdenum steel for quenching and tempering to EN ISO 683-2. Its closest American equivalent is AISI 4140.
Chromium and molybdenum give it a higher hardenability than carbon steels such as CK45, so larger sections still reach good strength and toughness after quenching and tempering. It is one of the most traded heat-treatable steels in the Iranian market.
Equivalents
- Material number (DIN)
- 1.7225
- EN name
- 42CrMo4
- Standard
- EN ISO 683-2
- AISI/SAE (approx.)
- 4140
- Iranian market name
- MO40, 7225
- Nominal density
- 7.85 kg/dm³
Chemical composition
| Element | Range (%) |
|---|---|
| C | 0.38–0.45 |
| Si | ≤ 0.40 |
| Mn | 0.60–0.90 |
| Cr | 0.90–1.20 |
| Mo | 0.15–0.30 |
Mass %, ranges of EN ISO 683-2; the heat certificate of the delivered material is what the contract relies on.
Hardness and delivery state
Supplied hot-rolled or annealed, and for mould making often quenched and tempered (Q+T). The hardness after quenching and tempering depends on the section size and the tempering temperature; state what you need in the request.
Heat treatment
MO40 is usually oil-quenched and tempered; its surface can be induction-hardened or nitrided. Welded parts need preheating and post-weld heat treatment.
Typical uses
- Highly stressed shafts and spindles
- Axles and power-transmission parts
- High-strength bolts and nuts
- Mould bases and holder plates
Delivery forms and size ranges
- Round bar
- Ø 10–1000 mm
- Forged flat and block
- 170×170 … 610×1200 mm
- Plate
- t 10–30 mm
The ranges the market offers, not a stock list. Rounds above about 100 mm are usually forged and traded in diameter bands.
Sizes and weights
Nominal weights at a density of 7.85 kg/dm³ (1.7225). The actual weight is weighed, and tool steel is usually sold by the weight of the cut piece.
| Diameter (mm) | kg per metre |
|---|---|
| Ø 20 | 2.466 |
| Ø 30 | 5.549 |
| Ø 40 | 9.865 |
| Ø 50 | 15.41 |
| Ø 60 | 22.2 |
| Ø 80 | 39.46 |
| Ø 100 | 61.65 |
| Ø 150 | 138.72 |
| Ø 200 | 246.62 |
| Ø 300 | 554.88 |
| Ø 400 | 986.46 |
| Width × thickness (mm) | kg per metre |
|---|---|
| 170 × 170 | 226.87 |
| 200 × 400 | 628 |
| 300 × 600 | 1,413 |
| 610 × 1,200 | 5,746.2 |
| Thickness (mm) | kg per m² | 2000×6000 sheet (kg) |
|---|---|---|
| 10 | 78.5 | 942 |
| 15 | 117.75 | 1,413 |
| 20 | 157 | 1,884 |
| 25 | 196.25 | 2,355 |
| 30 | 235.5 | 2,826 |
What to include in your request
- Grade and material number, and the standard if your drawing requires one
- Form: round, flat or block, square or plate
- Exact size: diameter, width × thickness, or plate thickness
- Cut length, or the number and size of pieces, or full bars
- Delivery state: normalised, annealed, pre-hardened or quenched and tempered, turned
- Quantity in kg or tonnes, place and date of delivery
- Preferred origin (made in Iran or imported), if it matters to you
Documents you can ask for
- EN 10204 type 3.1 inspection certificate (heat analysis and hardness)
- Ultrasonic test (UT) report for forged sizes
- Hardness report for pre-hardened or quenched and tempered material
Frequently asked questions
What is MO40 steel?
MO40 is the Iranian market name of 42CrMo4, material number 1.7225: a chromium-molybdenum steel for quenching and tempering to EN ISO 683-2. Its closest American equivalent is AISI 4140.
What is the density of MO40?
The nominal density of 1.7225 is about 7.85 kg/dm³ (g/cm³); the weight table on this page and the weight calculator use this value. The actual weight is weighed.
What is the equivalent of MO40?
1.7225 is listed in EN ISO 683-2 as 42CrMo4; its closest American equivalent is AISI 4140. Equivalents are approximate: if your drawing requires a specific standard, name it in the request.
Is MO40 the same as 4140?
MO40 (42CrMo4, 1.7225) is the close equivalent of AISI 4140 and their compositions are almost the same, but the element limits of the two standards differ slightly. If your drawing requires one of them, name it in the request.
How do I get a quote for MO40?
Send the grade, form and size, the cut length or number of pieces, the delivery state and the documents you need. We review the request and send you an offer.