4330V Modified Alloy Steel
A 4340-class steel with lower carbon and a vanadium addition for toughness: 220 to 240 ksi with good impact resistance — the aerospace and oil-tool grade for highly stressed components.
What 4330V is.
4330V (4330 modified) is a nickel-chromium-molybdenum steel with about 0.30 percent carbon and a small vanadium addition. The lower carbon improves toughness and resistance to shock loading compared with 4340, at the cost of some attainable strength, and the vanadium improves hardenability and impact strength. It is quenched and tempered, most often to 220 to 240 ksi, for airframe parts, bolting, drilling tools and other highly stressed components.
We machine 4330V components, studs and shafts from certified aerospace-quality bar and heat treat to the strength and hardness range on the drawing, with magnetic particle inspection as standard on request.
Chemical composition.
| Element | AMS 6427 | AMS 6411 |
|---|---|---|
| Carbon | 0.28–0.33 | 0.28–0.33 |
| Manganese | 0.75–1.00 | 0.65–1.00 |
| Phosphorus, max | 0.025 | 0.015 |
| Sulfur, max | 0.025 | 0.015 |
| Silicon | 0.15–0.35 | 0.15–0.35 |
| Nickel | 1.65–2.00 | 1.65–2.00 |
| Chromium | 0.75–1.00 | 0.75–1.00 |
| Molybdenum | 0.35–0.50 | 0.35–0.50 |
| Vanadium | 0.05–0.10 | 0.05–0.10 |
| Copper, max | 0.35 | 0.35 |
AMS 6427 limits confirmed by Michlin Metals and Aircraft Materials; AMS 6411 limits by Service Steel Aerospace, Michlin Metals and Tech Steel. Percent maximum unless a range is shown.
Mechanical properties.
| Condition | Tensile strength (ksi) | Yield strength 0.2% offset (ksi) | Elongation (%) | Reduction of area (%) | Hardness |
|---|---|---|---|---|---|
| AMS 6411 minimum, 220 ksi level (longitudinal) | 220 | 185 | 10 | 35 | — |
| Typical, tempered at 600 °F | 225 | 193 | 11 | 47 | 47 HRC |
AMS 6411 minimums for the 220 ksi level, longitudinal, confirmed by Service Steel Aerospace, EMJ and Tech Steel; Charpy V-notch 15 ft·lbf min. Typical values are from the Latrobe (Carpenter) Lescalloy 4330+V VAR datasheet. Strength follows the tempering temperature: 220 to 240 ksi needs a temper of about 500 to 700 °F.
Specifications that apply.
How 4330V ships from Houston.
- Machined components from certified bar
- Studs, threaded rod and U-bolts
- Hex bolts and cap screws
- Nuts, washers and spacers
- Pins, shafts and bushings
4330V fasteners we make.
Every item is manufactured to your drawing or standard in 4330V, imperial or metric, with an EN 10204 3.1 certificate.
What is 4330V steel?
4330V is an aircraft-quality nickel-chromium-molybdenum steel designed for toughness. Where 4340 uses 0.40 percent carbon, 4330V drops it to about 0.30 percent and adds vanadium, so it can be tempered to 220 ksi and still meet a Charpy requirement. It is supplied to AMS 6427 in aircraft quality or to AMS 6411 vacuum-arc remelted, and is used for airframe components, bolting and oil tools where a brittle failure is unacceptable.
Testing, certification and marking
- Tensile, hardness and Charpy per heat-treat lot on request
- Magnetic particle inspection after heat treatment on request
- Manufacturer's identification and heat number on every piece
- EN 10204 3.1 material test report; 3.2 witness available
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