SAE/AISI4140 ALLOY STEEL BAR
1. General introduction of 4140 alloy steel
SAE 4140/AISI 4140 is a low-alloy steel with added chrome-molybdenum, which is used as a reinforcing agent. In addition to chrome-molybdenum, the alloy steel has added iron and carbon. SAE 4140/AISI 4140 alloy bar has the characteristics of low temperature resistance, high temperature resistance, non-magnetic, atmospheric corrosion resistance, etc.
2. APPLICATIONS of 4140 alloy steel bar
Because SAE/AISI4140 is characterized by high temperature resistance, corrosion resistance, wear resistance, low temperature resistance, and non-magnetic, the most typical use of SAE/AISI4140 is forging gears, shafts, spindles, etc. In addition, SAE/AISI4140 is also used in automobile, agriculture, defense industry, aerospace and oil and gas.
3. Chemical composition of SAE/AISI4140 ALLOY STEEL BAR
| 4140 ALLOY STEEL CHEMICAL ANALYSIS | |
| C% | Carbon 0.38 – 0.43 |
| Mn% | Manganese 0.75 – 1.00 max |
| P% | Phosphorus 0.035 max |
| S% | Sulfur 0.040 max |
| Si% | Silicon 0.20 – 0.35 |
| Cr% | Chromium 0.80 – 1.10 |
| Mo% | Molybdenum 0.15 – 0.25 |
4. Alloy steel size in different supply conditions
| Supply condition | Diameter(mm) |
| Hot rolled | 10-300 |
| Cold drawn/peeled | 5-100 |
| Forged | 200-1000 |
5.SAE4140 in different standard
| ASTM | 4140 |
| JIS | SCM440 |
| DIN | 1.7225/42CRMO4 |
| GB | 42CrMoA |
6.Production process of hot rolled alloy steel bar 4140 4130
Producition process of hot rolled alloy steel bar 4140 4130
7.We can provide 4140 1430 4150 alloy steel bar treatment
- Surface treatment: peeling, turning, grinding, milling, drilling, boring
Heat treatment: normalizing, annealing, quenching + tempering
- Heat treatment of alloy steel
Heat treatment is performed after hot working to make the steel suitable for working and to meet the range of mechanical properties specified for the specific application of the steel.
- Alloy steel annealing
Grade 4140 forgings can be annealed by transferring the forgings directly from the forging process to a furnace at temperatures between 1450 and 1550ºF(790 to 840ºC), held for a suitable time, and then cooled to form a structure suitable for machining. This treatment is most suitable for simple shaped parts. If some areas of the forging are finished at much lower temperatures than others, a uniform structure cannot be obtained, in which case spherodizing annealing can be performed at around 1380ºF(750ºC). It is safe to say that experience alone can determine the best type of annealing treatment to use before processing.
8. Influence of alloying elements on rigid heat treatment
- Effect on austenitizing — most alloying elements (except nickel and cobalt) slow down the austenitizing process. Therefore, higher heating temperature and longer holding time are required during heat treatment than carbon steel. — Carbides do not decompose.
- Effect on austenite grain size — most alloying elements have the effect of hindering austenite grain growth. But manganese and boron, on the contrary, can promote austenite grain growth, so, except manganese steel, alloy steel is not easy to overheat when heated. This is beneficial to obtain fine martensite after quenching; It is also conducive to increasing the heating temperature, so that more alloy elements are dissolved in austenite to increase hardenability and improve the mechanical properties of steel. [2]
- Influence of alloying elements on over-austenitic transformation — all alloying elements except cobalt shift the C curve to the right, reducing the critical cooling rate of steel and improving the hardenability of steel (FIG. 7-4). Some alloying elements also change the shape of the C curve. In addition, most alloying elements also decrease the Ms point.
9. FAQ
- Is alloy steel stronger than steel?
Low alloy steels have less than 8% total alloying elements in the composition, these steels have better hardness and resistance to wear over carbon steel but tend to have less tensile strength. The high alloy steels have more than 8% alloying elements and have better properties than those of the low alloying steels.
- Is alloy steel better than stainless steel?
Alloy steel is more resistant to wear and tear compared to stainless steel. Alloy steels are easier to weld compared to stainless. Though stainless steel is weldable, the process is not easy as other welds. Alloy steel is less expensive and can easily be machined compared to standard stainless grades.
- Is alloy steel better than aluminum?
While aluminum does increase in strength in colder environments, it is generally more prone to dents and scratches than steel. Steel is less likely to warp or bend from weight, force, or heat. These resistant properties make it one of the most durable industrial materials.
- Does alloy steel rust easily?
For example, carbon is mixed with iron to make steel, an alloy of iron. As strong as alloy steel is, it doesn’t make it any less vulnerable to rust when exposed to the elements since it is ferrous (containing iron).
- Does alloy rust in water?
Aluminum alloys contain almost no iron, and without iron, the metal will not rust, but it will oxidize. When the alloy is exposed to water, aluminum oxide film forms quickly on the surface. The hard oxide layer is resistant to further corrosion and protects the underlying metal.
