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Forged???

Discussion in 'Rifle Country' started by TimH, Apr 30, 2003.

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  1. Slamfire

    Slamfire Member

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    As Daniel has alluded to earlier, proper heat treatment is far more critical than method of fabrication or even material. You can surf knife forums if you want to verify that, you don't get the heat treatment right, the part is not going to handle the loads, or cut the bacon.

    Heat treatment is something you don't hear much about, but I have talked to folks in the firearms industry, complicated parts, such as the M1911 slide with thick areas, thin areas, non symmetrical areas, it is easy to get the heat treatment wrong.

    And you would be surprised by how much they have to derate the material properties of something that has a weld.
     
  2. Kurt_D

    Kurt_D Member

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    Wow, I'm not reading this whole thread but forgings are stronger than the same sized/shaped casting. I mean really is it that hard to understand?

    examples:

    Car parts - universally known that forged cranks and pistons (as well as other parts) are stronger than the cheaper cast versions. I'd love to see some of ya'll try to tell some racers, teams, mechanics that cast is better...

    Aircraft - once again all critical parts (that are metal) are forged for strength. I guess you guys need to tell Boeing, Lockeed, etc. that their wasting money not using cast parts because heat treating is somehow going to work majic.

    In AR15s - search AR15.com, you will find several threads on cracked/broken cast recievers and almost none on forged/billet. I know cast is good enough for 99% of civi use but in this case facts are facts - cast is weaker.

    In swords - a hammer forged blade will be stronger than cast one. Yes they both need to be heat treated but the fact remains.

    In knives - good ones use steel that is rolled into sheets by high pressure rollers, just like forging uses high pressure blows to shape a product. Of course heat treating is the heart of the blade but a casting will not be as strong as rolled/forged steel.

    Yes, there are different alloys and you can change sizes but with all things equal (same alloy/heat treating/size) forged will always be stronger than cast.
     
  3. General Geoff

    General Geoff Member

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    ^^unless there's a part that's shaped in a way as to make forging impossible, but that improves application-specific strength, and can only be fabricated via casting.
     
  4. Kurt_D

    Kurt_D Member

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    true, true.

    But then you probably could mill it from rolled billet which should be stronger than cast, if the extra strength is needed. Only problem there is cost goes through the roof.
     
  5. General Geoff

    General Geoff Member

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    Are billets not cast?
     
  6. SwampWolf

    SwampWolf Member

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    cracked butt: I believe Ruger MkII and MkIII pistols are still being fabricated from "stamped steel", not the investment cast process- and I hardly think they are in any way inferior to Sig "Trailside" pistols.

    Concerning the difference in prices between the Ruger M77 Mark II and an equivalent Winchester Model 70; in comparing the two, using each one's 2005 catalog, the Ruger"Standard" model retailed for $716.00 and the Winchester "Classic Sporter III" model retailed for between $778.00 and $810.00 (depending on the caliber). These are the two models from each company that are the closest in features and configuration. In my experience, this disparity in price has always been reflected in "street prices" and the price spread has always favored Ruger. I can't speak for where you shop but, in my neighborhood at least, Ruger has always offered the better "value".

    Finally, if Miroku (or some other foreign company) starts making Model 70s again with forged receivers, one has to figure in the cheaper labor costs as part of the equation (in determining which manufacturing process offers the biggest bang for the buck).
     
  7. H2O MAN

    H2O MAN member

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    I chose forged Chinese receivers for all of my M14s for one reason:

    USGI parts fit and function in these receivers better than any other receiver except USGI and the rare SEI receiver.

    NOTE: My cast Springfield receiver was a little out of spec in the scope mount stripper clip guide area, but it was fine otherwise.
    However, All of the cast reproduction parts failed with less than 400 rounds fired. USGI and some Chinese parts are better.
     
  8. daniel (australia)

    daniel (australia) Member

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    Maybe you should do more reading.


    Well, you aren’t really comparing apples with apples, nor are you looking at the right property in those examples. If we compare a forged steel crankshaft or con-rod with one of conventional spheroidal graphite or nodular cast iron the forged steel will generally be significantly better, at least for racing and high duty. That is not because of strength though but resistance to fatigue failure, which is admittedly much better for forged steel than any cast iron or even the general run of cast steel.

    Fatigue is a big factor for cranks and rods, but not rifle receivers: a crank and rods will undergo more load cycles in a few seconds at full noise than a rifle receiver will undergo in its entire service life. That is why as well as specifying a forged crank your tuner will also be obsessive about radiusing all corners, shot peening and polishing, crack testing, and balancing, all to reduce the likelihood of fatigue cracks being initiated. None of this is relevant to rifle receivers.

    There are better materials than these for racing car components too, such as Metal Matrix Composites, already seen and then banned from use in F1 pistons. MMCs are generally produced by casting or else powder metallurgy, and have particular advantages for pistons due amongst other things to the thermal loads.

    F1 engines do use investment castings in the form of valves, valve-train components, blocks, gearbox housings and a myriad of others. The rules specify a steel crank though, so that is what is used.

    Heheh – no need to tell them, they already know:neener:.

    In fact about 10 years ago Boeing’s CEO gave an interview which he circulated to the company’s engineers to the effect that they should begin a targeted program to replace forgings, assemblies or fabricated parts with cast components. Among other things he expressed the view that Boeing could achieve a 20-35% reduction in tooling alone by converting a fabricated assembly to a cast component. Boeing has put that approach into effect very successfully.

    And Lockheed?

    It used to be the case that cast components in aircraft had to be spec’d with a built in fudge factor on strength, because they were thought to be less strong and reliable (and back then, probably were). That factor is rapidly becoming a thing of the past as it is recognised that a sound casting can indeed be just as strong as a forged one or a fabrication.

    As well as being as strong, castings can be developed more quickly and at less cost. They can also be produced with such features as coolant ducting, which can’t easily be done with other techniques, and complex shapes can be produced in one piece saving enormously on assembly time and warehousing complexity. That is why they are forming more and more of the structure of modern aircraft, as well of course as the major components of their engines. Just ask Boeing and Lockeed:p

    I would be surprised if it was solely due to the fact they were cast. As I said earlier, it is perfectly possible to make bad receivers by either casting or forging. Witness the fact that well over a million Springfield 1903 models had heat treatment problems which led to a number of failures and to these low-number receivers being considered less than safe. That doesn’t mean forging is a bad technique, and nor does the alleged failure of some unquantified number of AR15 knock-offs. Can you point to what aspect of their failure is attributable to being cast, and not to poor heat treatment, poor quality control or other factors?

    I doubt that anyone has tried making swords by modern casting methods, but there are indeed knives being made that way, and the best of them have some very good properties. Strength is of course only one property of a good knife. Certain cast cobalt alloys have good strength coupled with excellent wear resistance, good cutting properties and good corrosion resistance. There are also high end cast stainless knives such as the Boye “Dendritic Steel”, as well as more prosaic but also more widespread applications such as surgical blades, shears and so on which are well proven.

    No longer necessarily true, and there are other advantages one process might have over the other including not only the physical properties of the finished article, but time to market, development and tooling and production costs, and even whether you can make it that way at all.

    Getting back to rifles though, the well-proven reality is that investment casting is being used, much more widely than just by Ruger. Browning, Sako, Miroku and many others are also using this technique. With proper heat treatment and QA it is well proven as a means of making sound receivers and other firearm parts, just as with proper heat treating and QA forging can be used, or machining from bar or seamless tube stock. There is no longer any technical reason why a receiver made by one method or another, all else being equal, should be any less reliable or durable than another.
     
  9. Reyn

    Reyn Member

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    Good post Daniel. Interesting.
     
  10. Boston T. Party

    Boston T. Party Member

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    Regarding my cast-steel receiver SA M1, Ron spoke of
    the cast steel being the issue vs. the heat-treat.
    I no longer have that gun, so we can't test surface
    and core hardness.

    I understand how important heat treatment is, regardless
    of forged vs. cast steel parts.

    Ron Smith likes the Chinese M14S forged receivers, but
    they are too soft and need to be re-heat-treated (a
    service he offers).

    __________
    from daniel:
    I can think of a perfect example:

    Ruger's Model 77 Frontier rifle, whose barrel (theoretically) should have
    been cast to include an integral forward mount for the Scout scope.

    Instead, Ruger chose to use "Accurate hammer-forged, heavy barrels" . . .
    http://www.ruger.com/Firearms/FAProdView?model=17915&return=Y

    . . . and then affix a 6.625-inch "scout rifle" barrel-mounted rib.

    [​IMG]



    That rib is a separate piece, attached with four screws and two pillars:

    [​IMG]

    Why did Ruger go to all that seemingly extra trouble?

    Boston

     
  11. H2O MAN

    H2O MAN member

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    Yes, Ron really likes the Chinese M14 receivers - they are 2nd best behind his own SEI receivers.
    I'm told LRB will soon tie for 2nd best if they keep making the changes Ron has suggested.


    A small number of the receivers were soft and needed to be re-heat-treated, but most do not need this service.
    To date, Ron has built for me four rifles on Chinese receivers - he checked all 4 for hardness and did not have to heat treat them.
    My policy with Ron is "if it needs it - do it" and the results have been outstanding :D
     
  12. JesseL

    JesseL Member

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    Just a guess here:

    Because they're already set up to make hammer forged barrels, and it's ultimately cheaper to drill & tap their existing barrel and affix a short rib, than it would be to add a parallel manufacturing process just for casting and machining barrels with integral ribs. It's really much less trouble.

    It's all about making the most of the equipment and processes they already have. I don't think that Ruger's Newport NH facility; where their rifles are made; is set up to do button or cut rifling of rifle barrels. The barrels made in Prescott for Ruger's centerfire pistols are cast as one piece with integrated locking and camming surfaces, and then have their rifling cut.
     
  13. JohnKSa

    JohnKSa Member

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    I believe they already have the ribs as well. Isn't it pretty much identical to a part on one of the No. 1 models?
     
  14. daniel (australia)

    daniel (australia) Member

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    Yep, if you're already tooled up to produce barrels for your whole range of rifles by rotary hammer forging, which involves vast capital cost but very low per-unit cost, and you have tooled up to make the little quarter rib for another line via investment casting, why would you set up a completely separate and new process for a niche model? It makes far more sense to mix and match from the existing parts bin.

    Besides which, the rotary forging used for barrel-making, like investment casting, is pretty much a net-shape or near net-shape process anyway - you can produce the exterior profile, rifling and even chamber all in one process, and it is hugely efficient. I very much doubt you could produce barrels much more efficiently or economically. You produce a little quarter rib, for which you already have the tooling, for a few cents a unit, screw it onto an otherwise standard product and voila, a new model for the marketing department . Production engineering at about its simplest.

    Actions of course are a whole different ball game: it is a long way from the forging to the finished product - a forged action requires complex multi-axis machining, and a fairly substantial amount of it. That costs.
     
  15. Boston T. Party

    Boston T. Party Member

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    from daniel:
    Good point, thanks.

    However, I remain very skeptical that a cast-steel rifle barrel (of
    forged-steel thinness/weight) would be suitable for 50,000+ c.u.p.
    rifle cartridges.

    Boston
     
  16. harrydog

    harrydog Member

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    I know it's apples to oranges, but in high performance automotive applications where high RPM and high stresses will be encountered, forged or billet steel crankshafts and connecting rods are always used as opposed to cast cranks and rods.
     
  17. Ash

    Ash Member

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    This racing car angle is interesting, particularly since racing engines don't last very long. Granted, they are subjected to tremendous stresses, but these great and wonderful forged parts are never expected to endure long-term. They are wonderfully strong and capable for short-term use, but they are worn out very quickly. Of course, a cast part might just wear sooner, but their application is completely different than, say, my Cherokee which has 230,000 miles - hard miles - on it.

    Naturally, I cannot comment on whether or not a forged part would be holding up well at this mileage standard, but to compare the parts in race cars tends to point towards parts to be used very hard but not very long. That is doubtlessly not the goal of those posters defending forgings, but do I want a race gun to last 1000 rounds or do I want a rifle to last 200,000 rounds? By the way, FN not only changed the Hi-Power to cast, but also the FAL. Nobody says the forged Imbel FAL is better than the cast FN FAL.

    Ash
     
  18. Slamfire

    Slamfire Member

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    The engine has to last one race, then it is completely rebuilt. I was told by a guy in the business, that if you expect to race, the minimum amount of cash you need is $30 million per year. And that was a couple of years ago, this might be up to $50 million now.

    Priorities are entirely different when cost is not an issue and winning is the only measure of success and guarantee of future financial solvency.
     
  19. Ash

    Ash Member

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    That's my point. Racing tires don't last an entire race and the engine lasts one race. You can say that forged parts are used in racing engines, but I can dismiss such engines as pieces of crap because they don't last more than 500 miles. Heck, a Trabant engine lasted longer than that! Heck, why not buy Quaker State oil since they are used in so many race cars!

    The point is, the argument is not really suitable as such engines don't last long. The flip side, of course, is that they are very high performance when they are being used and as a part of that, some components are not scrapped after every race. All the same, the comparison is very easy to dismiss.

    Ash
     
  20. Boston T. Party

    Boston T. Party Member

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    Given the cost of replacing/rebuilding race-car engines
    after every race, you'd think the cost savings of cast
    parts would be alluring.

    Forged parts are more expensive. There's a reason why
    teams pay for them.

    Oh, I'd bet that somebody will in time.
    Maybe me!

    Boston

     
  21. Stinkyshoe

    Stinkyshoe Member

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    FYI, some Kimber 1911 Barrels are also cast. That's kinda scary, considering they are supposed to be some of the best 1911's. Funny how advertising works...:uhoh:
     
  22. harrydog

    harrydog Member

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    It's not only racing engines that use forged cranks. Most high performance road cars do and in fact many regular road cars use them. Honda, VW, Audi, Subaru, Porsche are some that immediately come to mind and some of these cars last 200K or 300K miles. So forged parts don't wear out any more quickly than cast parts.
    Racing teams use forged parts because cast parts probably wouldn't even last through one race.
     
  23. Shear_stress

    Shear_stress Member

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    Not sure where you picked that one up. Their barrels are forged, just like their slide sand frames.
     
  24. Slamfire

    Slamfire Member

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    I know for a fact that big diesel engines use cast iron cranks. I had two tours of a Caterpillar engine plant. Both times I saw big cast iron crank casting being machined and installed in the largest darn engine blocks around. We are talking about 1500 HP engines being considered small engines in that plant. Monster engines, things with 20 cylinders. A cost of a $70 K Porsche would not equal the price of two months fuel bill.

    The first overhaul is about 12,000 -15,000 hours. And that is basically seals liners, rings. Definitely not time for a crank change. Lifetime of a 200,000 mile car, about 3,333 hours at 60 mph.

    Casting work fine in the proper application.
     
  25. Ash

    Ash Member

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    Boston,

    It remains that race cars don't have long service times. And longevity is the point. Arguing that a forged part in a race car equals longevity is no argument at all. Said forged part lasts a short time and is replaced. This is not an argument either pro or against either form of manufacturing, only that the race car comparison is not valid.

    And, still, nobody claims that FN-FAL's are inferior.

    Ash
     
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