The quality of steel in war production no4s

[ssj]

Ive read a few comments in my travels of google that the steel of the Savage made receivers was better quality (no defination of what that means mind). Since it looked like the comments came from Americans where everything is always better, it may well be bull....or is there some truth to this?

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[breakeyp]

I would lose no sleep over this. US steel specifications would be to US SAE (Society of Automotive Engineers) which are a very detailed receipt of the various components needed to make various grades of steel and outlines the physical performance specifications to be expected from this grade of steel. UK has callouts that are compatible but historically have been a little looser in definitions of ingredients and performance. UK drawings often use specifications relating to the name of the manufacturer and his definition of mild steel etc. I could never get a clear understanding of what they did if the company went out of business. Either way the job got done in an outstanding manner. Certainly standards would have to have been relaxed at times due to enemy action.

[Bruce_in_Oz]

It's not just the steels.

The heat-treatment is vital in achieving the correct hardness, "springiness" etc.

Over the years I have noticed that the single component that I have seen fail catastrophically, most often, is the cocking piece on No 4s.

These mostly break just forward of the grasping portion at the rear. ALWAYS, the failed component shows a coarse crystalline stricture on the surfaces of the fracture.This clearly indicates poor heat-treatment (or VERY poor material) of the component. Poor machining can also leave "scratches" on the surface: these turn into "stress risers", ESPECIALLY after hardening, and are a good place for cracks and breaks to start.

The cocking piece is meant to be differentially hardened: The rear has to be just soft enough to run "chaser" taps through for final thread cleaning, the middle has to be tough enough to resist wear at the "safety" notches and the little safety stud on top, and the front has to be ALMOST "glass hard" to provide a robust and long-wearing surface for the engagement of the sear.To achieve all that in a component as small as the cocking piece is a challenge, more-so because it is not just a simple, flat, rectangular bar of steel.

The final thing is that the finished, heat treated component should not be warped or otherwise distorted by the process.Note that in the SMLE series, every "steel" component was made from a tightly specified "mild (low-carbon) steel or "malleable cast iron" and "alloy" steels were NOT permitted as substitutes except after testing for suitability by the government testing laboratories. This was the case even when desperate times brought about the "peddled scheme" (hundreds of small sub-contractors).

Obviously, the same should have applied to The No4, but by the late 1930s, "alloy" steels were in common use in all similar industrial processes. Not only is the material important, but the heat treating regime is CRITICAL. When the 'instructions talk about "cherry red" does that mean in a gloomy shed or an outdoor forge? The advent of controlled conditions and the magic of the pyrometer eventually tidied that issue up, but not before BILLIONS of components for all manner if things had been made.

It's not just firearms; the technology of the gunmakers made steam power and the motor industry possible. Precision boring, honing, differential heat-treatment etc all originated the the gun business, as did the idea of interchangeability. And then there was the required degree of precision and its effect on metrology.

Final catch: steel (and all iron products) AGE. The crystal structure is only partially "frozen" the last the last time it comes out of a furnace. The tendency is for the crystals INSIDE the component to GROW, very slowly over time. This is common to all iron-based alloys and is a good reason NOT to be dry or otherwise firing your three hundred year old flintlocks; the barrel probably won't burst but there is a good chance you will break the "cock" (hammer). I saw that happen to a near-mint 1700s vintage Naval pistol a few years back; not pretty, and VERY hard to repair!

[ssj]

Yes interesting how armaments has so often driven or been behind technological change.
regards

[Peter Laidler]

Your description is as good as any workshop processing lecture I have heard Bruce. And everyone out there in forumland, please read - and read again that last paragraph.

Thanks Bruce

[WarPig1976]

What's the deal with Steel and corrosion Pre/Post nuclear detonation. I read somewhere steel now requires additives to keep from rusting faster??

Edit=This is what I'm talking about, steel prior to detonation is not contaminated. Doesn't pertain to no4's but kinda neat to know that even steel produced today is "Radioactive" and not as "pure" as the day before Trinity.
http://en.wikipedia.org/wiki/Low-background_steel

[Ridolpho]

Comments regarding the "aging" of steel are an eye opener. I tended to think of metals as impermeable and not subject to low temperature recrystallization. I've heard of hydrogen embrittlement, facilitated by hydrogens ability to diffuse through the lattice- is that what's happening? Now that the concept has been broached the question must be asked- is aging of gun quality steels an issue at the time scale that concerns us- ie 100 to perhaps 200 years and in barrels/ actions of breech loading high powered rifles?

Ridolpho

[Rumpelhardt]

I thought the Swede's said they had the best steel? I guess it's all in who you talk to.

[breakeyp]

When I was being thumped to learn a passing understanding of Metalurgy as part of a mechanical engineering degree, several things are remembered with no memory of why but they do remain:

1. Only steel is considered to have an infinite life (if the iron moths stay away). I was told Aluminum has an effecive life of 40 years. Memo to those who gad about in WWII period airplanes. Interestingly, I was never exposed to how to work this information into calculations or factors of safety or how the failure mode would develop.

2. Nylon thread is stronger in tension than equivalent steel. We don't make buildings out of nylon as it sucks in shear (shear--grab material in one hand pull to you and push away with the other hand)

I miss my materials/fasteners section at Ford Motor. They always could help with problems like these.

[ssj]

When I was being thumped to learn a passing understanding of Metalurgy as part of a mechanical engineering degree, several things are remembered with no memory of why but they do remain:

1. Only steel is considered to have an infinite life (if the iron moths stay away). I was told Aluminum has an effecive life of 40 years. Memo to those who gad about in WWII period airplanes. Interestingly, I was never exposed to how to work this information into calculations or factors of safety or how the failure mode would develop.

2. Nylon thread is stronger in tension than equivalent steel. We don't make buildings out of nylon as it sucks in shear (shear--grab material in one hand pull to you and push away with the other hand)

I miss my materials/fasteners section at Ford Motor. They always could help with problems like these.

=======
It depends on the steel. Mild Steel will probably last a long time....fancy high tensile steels on the other hand do age. Take HY80 (if I recall that designation right) its a high grade tensile steel used for sub hulls, but over time it laminates from the pressure changes, so after say 20 years the sub cant dive as deep safely and is in fact scrap...