4140 PH / 4142 PH Steel - 1.7225+QT - 42CrMo4 - Chrome-Moly

What is the difference between 4140 PH and 4142 PH steel?

4140 PH and 4142 PH are nearly identical but for a slightly higher carbon content for the 4142 PH. Where the steel composition of the 4140 PH has a carbon content of 0.38 to 0.43%, 4142 PH has carbon content of 0.4 to 0.45%. 

What is 4140 PH / 4142 PH steel used for?

Applications for this 4140 PH / 4142 PH flat stock steel include: arbors, flanges, collets, bending dies, crankshafts, clutch parts, forming rolls, and short run stamping dies.

Is 4140 PH/ 4142 PH steel stainless?

4140 PH / 4142 PH is, even with a chromium and molybdenum content, not a classic 10.5% chromium stainless steel. It belongs to the group of high grade structural steels.

Is 4140 PH / 4142 PH corrosion resistant?

On a scale where 1 is low and 6 is high, the corrosion resistance for 4140 PH / 4142 PH stands at 2. 4140 PH / 4142 PH has some corrosion resistance due to the chromium and molybdenum content but will rust when corrosion has set in and sustain the same damage as other non-corrosion resistant steels.

Is 4140 PH magnetizable? 

4140 PH / 4142 PH steel is magnetizable and suitable for magnetic clamping.

Heat treating the 4140 PH / 4142 PH heat treatable steel

The 4140 PH / 4142 PH is not normally heat treated as it is delivered in a pre-hardened condition. Should the need for a higher hardness arise please follow the hardening steps below starting with annealing the 4140 PH / 4142 PH.

4140 PH / 4142 PH Annealing

Uniformly heat the work pieces to 1256 - 1328°F (680 - 720°C), followed by a slow cooling in the furnace to reach the annealed hardness of approx. 217 BHN. 

Stress relieving the 4140 PH / 4142 PH heat treatable steel

4140 PH / 4142 PH is heated slowly through to 900°F (482°C) and soak for 1 hour per inch (25.4 mm) thickness, then cool the material in the furnace or air to room temperature. 

Normalizing heat treatable 4140 PH / 4142 PH

The 4140 PH / 4142 PH can be normalized before hardening. Heat to 1544 - 1616°F (840 - 880°C), followed by air cooling.

Hardening heat treatable 4140 PH / 4142 PH 

4140 PH / 4142 PH is pre-hardened material, to reach a higher hardness the material has to be annealed, as described above, and then it can be re-hardened.

After hardening the material can achieve a working hardness between 262 and 456 BHN (27 - 48 HRC).

Quenching heat treatable 4140 PH / 4142 PH 

4140 PH / 4142 PH can be quenched in oil to room temperature and then should be tempered  immediately.

Tempering heat for heat treatable 4140 PH / 4142 PH

4140 PH / 4142 PH can be tempered at 1004 - 1256°F (540 - 680°C), the higher the tempering temperature the softer and more ductile it gets. In general hardness and ductility are determined by tempering the material, the higher the ductility the lower the hardness which is true for the reverse as well. Apart from the advantage to give the steel the wanted and needed properties the material can be stress relieved, is less likely to crack and has a better deformation behavior by tempering it. 

Tempering the 4140 PH / 4142 PH heat treatable steel

As delivered: Alloy 4140PH / 4142 PH does not require a tempering as it is pre-hardened. If this material should be re-hardened, follow the annealing and hardening process as described above.

Re-hardened: Alloy 4140 PH / 4142 PH can be tempered at 1004 - 1256°F (540 - 680°C) subject to hardness and according to the properties required. Cool in air after the treatment. 

Dimensional changes of heat treatable steel 4140 PH / 4142 PH

4140 PH / 4142 PH has a creep resistance up to a temperature of 1004°F (540°C) and is able to sustain its properties when exposed to relatively high working temperatures over a longer time.

Electrical Discharge Machining (EDM) of the 4140 PH / 4142 PH heat treatable steel

It is possible to EDM this steel grade in the annealed and hardened condition. As for all EDM work the recast layer has to be removed thoroughly by stoning and polishing.

Can 4140 PH / 4142 PH heat treatable steel be nitrided?

4140 PH / 4142 PH can be nitrided to give this steel grade a harder surface layer.

4140 PH / 4142 PH Machinability

This grade is easily machinable after it has been heat treated to produce the microstructure required for the best machinability.

Can 4140 PH / 4142 PH be forged?

In its PH condition, forging can be challenging. Forging this steel grade should be done in its annealed or normalized condition.

Annealed or normalized: 4140 PH / 4142 PH can be forged in a temperature range of 1652 - 1832°F (900 - 1000°C) followed by a very slow cooling in still air or sand. 

2CrMo4 weldability?

Welding may only be done in the annealed or normalized condition. All conventional techniques may be applied then. 

Annealed or normalized: In order to prevent cracking, preheat to 350-650°F (177-350°C). Due to the level of carbon in this steel, pre- and post-heat is recommended. Cool slowly to prevent/reduce embrittlement. If welded in the heat-treated condition, which is normally only done for repairs, mechanical properties are affected and a post-weld heat treatment should be performed. Welding pre-heated parts, it is recommended to stress relieve the parts before at a temperature 60°F (15°C) below the original tempering temperature in order to prevent cracking.

Wear resistance of heat treatable steel 4140 PH / 4142 PH

On a scale where 1 is low and 6 ist high, 4140 PH / 4142 PH comes in at a score of 3.

Tensile strength of the 4140 PH / 4142 PH heat treatable steel

4140 / 4142 has a tensile strength of approx. 104.4 KSI on delivery (0.145 KSI = 1MPa). In order to reach this value, a tensile test is performed to show how much force is needed to stretch or elongate a sample before it breaks.

4140 PH / 4142 PH  Yield strength

The yield strength of 4140 PH / 4142 PH is at approx. 95 KSI. This shows when the material starts to show plastic deformation.

4140 PH / 4142 PH working hardness

The working hardness for this material grade is in a range of 262 - 456 BHN (27 - 48 HRC)

4140 PH / 4142 PH specific heat capacity

This value shows how much heat is needed  to heat 1lb of 4140 PH / 4142 PH by 1 Fahrenheit.

4140 PH / 4142 PH Continuous time-temperature-transformation-diagram

This diagram shows micro changes over time at different temperatures. Those are important during heat treatment as they show information about the optimum conditions for processes such as hardening, annealing and normalizing.

4140 PH / 4142 PH  Isothermal TTT-diagram

This diagram shows the structural changes at micro level over time at a constant temperature. It shows at what temperature and after what time different phases, e.g., perlite, martensite or bainite start to build.

4140 PH / 4142 PH Steel Properties

Hot working the heat treatable 4140 PH / 4142 PH

This steel can be hot worked at 1500 - 1900°F (816 - 1038°C), it maintains its properties even after long exposure at the high working temperatures.

Cold working the heat treatable 4140 PH / 4142 PH

In its annealed condition, this steel can be cold worked with all the conventional methods.

4140 PH / 4142 PH  Steel density

The density of 4140 PH / 4142 PH at room temperature (~68°F) is 0.284lb/in3 (7.85g/cm3).

Thermal conductivity of 4140 PH / 4142 PH heat treatable steel

The heat conductivity for the 4140 PH / 4142 PH at room temperature is at 42.6 W/(m*K) (313 BTU/(h-ft2*°F)).

4140 PH / 4142 PH thermal expansion coefficient

This diagram shows how much 4140 PH / 4142 PH might expand or contract when the temperatures change, which can be very important when working with high temperatures or strong temperature changes.

The specific electrical resistivity for the 4140 PH / 4142 PH

You can find the temperature dependent material constant (Resistivity) in the following table. The electrical conductivity is the reciprocal value of the specific resistance.

(*) 1 Ω m = 0,0254 Ω inch

Modulus of elasticity (Young’s Modulus) for the 4140 PH / 4142 PH

The relationship between stress and strain of steel is described in the modulus of elasticity (Young’s Modulus) and can be found in the table below with the according values and temperatures.

Is 4140 PH / 4142 PH a knife steel?

When choosing to make a knife or blade from 4140 PH / 4142 PH the hardness and corrosion resistance as well as wear resistance should be considered. Though possible this steel grade is not commonly used to make knives with. 

Datasheet for the 4140 PH / 4142 PH

As a 4140 PH / 4142 PH steel supplier we provide you with the datasheet for 4140 PH / 4142 PH in PDF format.

Alternatives for heat treatable 4140 PH / 4142 PH steel

With our patented ABRAMS STEEL GUIDE®, you are able to find an equivalent or an alternative to the  4140 PH / 4142 PH or a compatible steel and its properties in no time. 

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