Seeking 42CrMo4V Substitute 1

[Jstatham]

Having difficulty locating domestic source for 42CrMo4V in round bar stock, would appreciate advice on equivalent. Will be used for load bearing axle on heavy equipment.
Thank you

 

[metengr]

From what I could find, this material is supplied under a DIN Standard (1.7225), and is basically a Cr-Mo-V alloy steel. I am assuming that you are considering reverse engineering of this axle.

If so, you need to carefully investigate or determine the original specified mechanical properties of this steel before you can zero in on an equivalent material substitution.

Critical items to consider before you select a material;

1. Is this a thru-hardened axle? If so, what are the specified minimum mechanical properties (ultimate tensile strength, yield strength, percent elongation) for the load bearing axle?

2. Is there any surface hardening treatment of the original axle?

3. Toughness requirements for low temperature service?

 

[TVP]

The chemical composition range for this grade overlaps SAE 4140 and 4142, with 4142 being less available. It is unclear to me whether the V is supposed to be indicating "verguetet", which in German means hardened, or if it is indicating that vanadium should be added. V improves the hardenability, and helps to refine the austenitic grain size.

 

[alexit]

The V means added Vanadium but in small quantity. If it was a percentage addition it would be written as 42CrMo4V_ like 50CrV4 (similar to 6150.)

As Metengr wrote, to make an axle get a materials engineer involved to translate the existing product into a material and heat treating process(es).

 

[Carburize]

In the USA I would substitute 4145 or 4340

 

[lewtam]

My understanding is that a 'V' suffix indicates hardened, and if Vanadium is a required alloy, it is mentioned before the final number. The alloys are listed in the order of max to min content.

42 - avg carbon content
4 - indicator of alloy content according to a formula that I don't currently have handy. Similar to C.E. with each alloy weighted according to affect it has on final product. Higher number, higher alloy content.

42CrMo4V - Harderned & Tempered Chrome/Moly steel
42CrMoV4 (if it exists) - Chrome/Moly/Vanadium Steel - Chemistry specification only.

Get vendor material certs for 4140 they have in stock and pick the one closest to 0.42% C. Do a hardness test on your axle and heat treat accordingly. I recommend a UT of the bar before purchase if your axle is critical.

 

[unclesyd]

I have the 42CrMo4V material listed as equivalent to AISI 4140 under DIN 1.7225 with the following properties standards:
EN 10083-1, 10269, 17204

I also have a piece of inductioned hardened chrome plated shaft (42CrMo4V) for use with linear bearings . The shafts are also made with induction hardened C45.

Also have another reference to the material being 1.7225 (I think it is Cl 3)as the brochure is torn.

It appears as the V does indicate hardened as I have the material list as 24CrMo4 hollow bar stock.

It looks like 4140 (aircraft quality) would be a good substitute as stated lewtam.

 

[lewtam]

Unclesyd - I've seen the 'aircraft quality' designation on this site a few times now. What does it designate? All I've been able to find is a spec from the '70s that says aircraft quality alloy steels means the melt is vacuum degassed in production - a step that is hardly out of the ordinary these days. The term 'Aircraft Quality' does pop up here in Australia from time to time but none of the vendors can give me a satisfactory answer and I tend to think that it is marketing hype (at least in this country).

I know there are special aircraft grades like AMS 6382 - is that what you mean by 4140 Aircraft Quality?

LewTam Inc.
Petrophysicist, Head Stockman, Gun Welder, Gun Shearer, Ski Instructor, Drama Coach.

 

[Jstatham]

Thank you all. Deciphering these German prints can be the devil.

 

[TVP]

lewtam,

Yes, there are several SAE AMS standards for aircraft/aerospace quality 4140 steel. Depending on the product form, SAE AMS 6381 and 6382 are applicable.

 

[unclesyd]

lewtam,
It isn't hype in the USA, it is a legitimate callout to a reputable supplier. This callout will help insure that you have the requested product supplied generally under a AMS specification. This is an aid in getting the highest quality readily available material at reasonable price as you normally put a lot of value added work in the finished component. Since you wern't selling the component you wanted the best part obtainable.

We called this out on 4130,4140, and 4340 or 4340V material especially for shafting. The reason being that a times 4140 bar can be extremely crappy. As I recall our in house specification called out 4140 Bar CR annealed as per
Mil-S-5626, AMS 6349. This was for 1 1/4" bar and below. Our cutoff point for 4140 shafting was at 1 1/4". Above 1 1/4" we used 4340 or Maxel 3 1/2 or Astralloy V in really tough cases.
We got Magnaflux happy when we bought 4140 outside these specifications, i.e. forged blocks, stepped spindles, hubs.

Here is how one of our suppliers treats AQ

http://www.frysteel.com/data/MeettheMetals/showmetal.cfm?metal=aircraft#

 

[Carburize]

I have always considered "aircraft quality" to indicate material meeting the cleanliness requirements of AMS 2300 or 2304

 

[unclesyd]

Carburize

I looked at the Fry site and they have AMS 2301 and AMS 2304 to cover 4140. Most of the other materials are available under AMS 2300. I imagine that they carry 4140 that would meet all the spec’s with a little selection. Good 4140 AQ at times was hard to get because at one time the AMS type users tended to stay away from 4140 by jumping from 4130 to 4340, with 4340 being more predominate. Even then at times plain vanilla 4340 was in short supply as everyone was using the flavor of the week 4340V. This liked to have caused us to get in mess as a material (I think it was D6ac) was suggested a substitute for 4340 in a very high cycle, both mechanical and temperature, service.

I don't remember calling out the cleanliness spec’s routinely except on H11 and H13.

Being in the chemical and fiber industry we tended to stay away from the AMS spec's and the like, as you know it tends to be a rather sporty adder if not in the business.

For many years we depended on different vendors to supply materials that met our requirements and wasn't until the industry started coming apart that we had to pick up on tightening the specifications.

 

[lewtam]

Must be fantastic to have that range of choice for alloy steels. VAR in machinery steels is very rare and definately not off the shelf in Australia. VAR H13 is widely available and is one of my go-to's for specifications to replace items made from 4340 etc that continuosly fail in fatigue. Definite overkill in some situations but it hasn't let me down yet, and is much cheaper than E4340 (which has to be flown in from Singapore) here.

 

[Carburize]

lewtam - what do the gear people in Australia use? They often have demanding specifications for through hardening steels which can be used in other applications.

 

[lewtam]

Similar gear material to you guys, but with a mix of British grades thrown in.

For case hardening, the entry level is 8620 - the low carbon manganese and boron steels for basic gears just aren't available for the jobbing market. From there it's up to X4317 (bit higher Moly than AISI 4317) then the British EN36, and before the price of nickel went stupid EN39 (similar to 9310) was available for the real heavy duty stuff.

There's been a shift from flame and induction hardening gears to case hardening in recent years, but still plenty of jobs calling for larger sections of 4340 (usually servicing US sourced mining equipment). This large section 4340 is getting harder to find and quite a few change requests have left my desk in the last 18 months to change to carburized X4317 just based on material availability. I think they're ending up with a better gear to boot and have been pushing it for years, but very few were willing to change until the 4340 supply dried up.

 

[Carburize]

Interesting information thanks lewtam