Alloy & tool steel
16MnCr5 case-hardening steel (1.7131)
Manganese-chromium case-hardening steel for gears, pins and cams; round bar.
In the Iranian market 'semante' is the name for case-hardening steels, and 7131 is one of the most common: 16MnCr5, material number 1.7131, to EN ISO 683-3. Its closest American equivalent is AISI 5115.
It is a low-carbon steel: after machining, the part is carburised and hardened, which gives a hard, wear-resistant surface over a tough core. Nickel case-hardening steels such as 1.5920 (18CrNi8) and 1.6587 (18CrNiMo7-6) are for heavier gears and are separate grades.
Equivalents
- Material number (DIN)
- 1.7131
- EN name
- 16MnCr5
- Standard
- EN ISO 683-3
- AISI/SAE (approx.)
- 5115
- Iranian market name
- semante 7131, 7131
- Nominal density
- 7.85 kg/dm³
Chemical composition
| Element | Range (%) |
|---|---|
| C | 0.14–0.19 |
| Si | ≤ 0.40 |
| Mn | 1.00–1.30 |
| Cr | 0.80–1.10 |
Mass %, ranges of EN ISO 683-3; the heat certificate of the delivered material is what the contract relies on.
Hardness and delivery state
Usually supplied annealed, ready for machining. The final surface hardness comes from carburising, hardening and tempering at the heat-treatment shop, and the case depth is set by the part designer.
Heat treatment
The usual route: machining in the annealed state, carburising (gas or pack), direct or re-hardening, and low-temperature tempering. Specify the case depth and surface hardness on the part drawing.
Typical uses
- Gearbox and power-transmission gears
- Pins, gudgeon pins and bushes
- Cams and camshafts
- Parts that need a wear-resistant surface and a tough core
Delivery forms and size ranges
- Round bar
- Ø 20–850 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 (1.7131). 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 |
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 16MnCr5 steel?
In the Iranian market 'semante' is the name for case-hardening steels, and 7131 is one of the most common: 16MnCr5, material number 1.7131, to EN ISO 683-3. Its closest American equivalent is AISI 5115.
What is the density of 16MnCr5?
The nominal density of 1.7131 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 16MnCr5?
1.7131 is listed in EN ISO 683-3 as 16MnCr5; its closest American equivalent is AISI 5115. Equivalents are approximate: if your drawing requires a specific standard, name it in the request.
What does 'semante' mean?
In the Iranian market 'semante' means a low-carbon steel made for carburising (cementation). After carburising and hardening the surface is hard and the core stays tough. 16MnCr5 (1.7131) is one of the most common.
How do I get a quote for 16MnCr5?
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.