Technologia luf

[maziek]

hm o chlodzeniu tam nie bylo mowy

sądziłem, że po to ten płyn: "Proces obkuwania odbywa sie w strumieniu cieczy o skladzie..." bo to przecież nie obróbka skrawaniem, a więc ani smarowanie ani odbieranie wiórów.

Kucie na zimno nie oznacza szronu na kutym detalu

Domyślam się. Nie mam wyczucia ale wydaje mi się że młotki walące z siła około 120 ton z predkoscia 500-1000 razy na minute generują potworne ilości ciepła z niespreżystego odkształcania stali. Zwykłym młotkiem, któym może wygeneruje się siłę równą ciężarowi kilkudziesięciu kG, uderzając raz na 2-3 sekundy łatwo rozżarzyć pręt (wiem, bo próbowałem na fali jakichś zawodów kowali w TV). Potrzebna jest pewna sztuczka (którą zdradził zwycięzca zawodów - chodziło o odpalenie papierosa), polegająca na przesuwaniu strefy uderzeń ku końcowi preta - a tak właśnie przesuwa się strefa kucia na lufie. Co więcej zwycięzca w przeciwieństwie do tych, którzy przegrali wcale nie machał młotkiem jak stachanowiec, a tylko precyzyjnie plasował puknięcia.

[waliza]

No to wszystko jasne. Plyn jesli tam jest to na pewno do chlodzenia Zwlaszcza ze jego sklad to prawie sama woda.

[Apolinary Koniecpolski]

Jeżeli ktoś jest zainteresowany to mogę poskanować i podesłać całkiem fajny artykuł Ralpha F. Quinna "Shooting steel: secrets of rifle accuracy" (z Shooter's Bible numer 87 za rok 1996).

[Apolinary Koniecpolski]

Dosyć ciekawy* artykuł o produkcji luf:

http://v038357.home.net.pl/archiw/polow ... trona.html





*acz nie pozbawiony drobnych błędów

[Apolinary Koniecpolski]

Znów trochę do poczytania:

http://www.homegunsmith.com/cgi-bin/ib3 ... =4;t=26154

[Wesley]

Wedlug porzekadla "nie wszystko zloto co sie swieci" poszlem dobra droga czyli w lufy polskie i rosyjskie
Jedna z wielu wypowiedzi, ktora utwierdza mnie w tym przekonaniu.

"American Barrels in Com Bloc Rifles

US manufacturers fill the gap left by import bans

Time was, the American AK buyer could take home Chinese Polytech Legends, Norinco Mak 90‘s and several different country of origin parts kits that all included foreign manufactured chrome lined mil spec barrels. But over the past 40 years the passing of the 1968 Gun Control Act, Assault Weapons Control Act of 1989, and the 1994 Crime Bill have effectively ended the importation of foreign made "assault rifles”. The BATFE, in an open letter to Federally Licensed Firearms Importers dated November 22nd, 2005, directed that the importation of barrels originating from assault weapons or used in the manufacture of assault weapons would no longer be approved. And with that decree, com bloc AK barrels either in standalone format, or as part of a kit, ceased to ship to our shores.

It’s still legal to construct your own AK variant from parts kits as long as you are making the rifle for yourself and not producing for sale purposes. But it is becoming harder and harder to locate original mil spec AK barrels brought here prior to the current barrel ban. The US manufacture of AK type receivers has long since matured to the point where quality is on par with com bloc receivers. And adherence to parts count rules known as 922r, has created a cottage industry of stocks, trigger groups, and various sundry items necessary for easy compliance while giving the end user quality AK type rifles. But the production of barrels is an entirely different animal. Creating a barrel is typically beyond the means of even the most ardent AK home kit builder. A rifle barrel is the proverbial heart and soul of a firearms accuracy and longevity. And most firearm consumers buy their rifles ready to fire with little to no post production beyond the casual customization options such as finish, stock set or optics. So where does this leave the average AK shopper in regards to finished and mass produced AK variant rifles, since com bloc barrels are now a thing of the past?

Imported AK type rifles that enter the US in sporting format and are later remanufactured back to their original AK configuration are made by only a few companies and yet a quick perusal of the internet will garner multiple examples of AK rifles that began life as an AK variant with no in between metamorphosis from sporting to military style carbine. Several US manufacturers currently produce homegrown AK barrels. Some are chrome lined. Some are chromoly steel. Currently Arsenal, Inc., of Las Vegas, Nevada imports Russian Saiga rifles which are simply civilian legal, semi-automatic AK variants imported in what is known as "sporting” format. Upon arriving in the US Arsenal re-configures them back into the standard AK format. Century International Arms, Inc., imports Romanian AK variants in similar fashion. Both companies import products with com-bloc hammer forged chrome lined barrels. Both are able to do this due to the original state of the imported weapon being sporting and by following 922r imported parts count adherence. When studying the manufacture of AK variants available in the US it is helpful to have a basic understanding of the processes behind the manufacture of the components, with the key component being the barrel. AK barrel manufacture follows two basic methods: Button Rifling or Hammer Forging. While the end results garner like outcomes, the production processes to achieve the internal lands and grooves inside a barrel are very dissimilar.

Germany originated the hammer forging method of pounding out barrels during the Second World War, largely in response to their design of machine guns and assault rifles with their abusive cyclic rates, while America set upon perfecting the technique of button rifling.
First, let’s look at button rifling, what the term means and the underlying reasons for its continued adoption as a barrel manufacturing technology. Button rifling is the process of pulling a small dowel called a button, with the reverse shape of the rifling, through the bore to mold the lands and groves. The blank must then be stress relieved and contoured. The final step must be lapping because any residual stress will cause the barrel to open up. This is the opposite of what is desired for accuracy. Button Rifling is in wide use by smaller manufacturers since the technology has matured and the start up costs are much less than competing technologies such as hammer forging. Evolutionary developments in production techniques have pushed this craft near the zenith of maturity and a button rifled barrel by a competent manufacturer has the potential for match grade accuracy.

Now, let’s examine hammer forging. The basic method of hammer forging a barrel is quite different. First the bore of the blank is drilled, being slightly larger to accept the mandrel. Then the barrel blank is pounded uniformly as the mandrel, being one third the length of the barrel, is passed through so that the steel is compressed around the mandrel forming the lands and grooves. Hammer forging as a method of barrel making came about largely due to a need for mass quantities of weapons during World War 2. Manufacturers needed a way to quickly produce large numbers of barrels very quickly. With the wartime adoption of hammer forging it was possible to produce considerable sums of barrels for the wartime effort with acceptable accuracy for battlefield purposes. It couldn’t be said that accuracy was the foremost desire but rather the ability to churn out barrels in bulk.

In talking with Bill Alexander of Alexander Arms I had the very enjoyable opportunity to talk barrel manufacturing and firearms in general with an eye towards what these concepts mean for the AK variant enthusiast. With an entire career in armaments both as a designer of artillery armor and small weapons for the British Army, as well as working on classified projects for the British and US Federal Government, Bill is well versed in the field of arms. In discussing barrel manufacture I’ll admit I was surprised that the first things mentioned weren’t the details of, and the differences in, the techniques involved, but rather the procurement of raw materials and production costs. That these are the first things to consider as a manufacturer seemed rather obvious after they were discussed. When considering the materials involved in making barrels, it would be naïve to think that all steel is the same. Metallurgy is quite involved and like any raw material there are many different grades even within like types. Suppliers are always willing to work with manufacturers to provide materials to certain specifications but purchasing power does hold sway. The larger one’s purchasing power is the better one will be able to order according to quality. A smaller manufacturer simply will not be able to buy in sufficient quantity to negotiate for the highest grade materials at affordable bulk prices. This is nothing to say of the metallurgical knowledge one must possess to properly discern the quality of the steel being acquired. Supply and demand and purchasing power in the free market are forces that work across scores of industries and the firearms industry is not immune to this. Button rifling being the preserve of the small manufacturer, a small builder would have to be able to afford high quality clean steel to even think of creating true military spec AK barrels on par with Russian hammer forging. Another roadblock in the way of creating authentic AK specification barrels using button rifling on a small scale is the simple fact that button rifled barrels are softer simply because the steel must be softer to allow the button to be pulled through. This necessitates the need for proper post production heat treating due to the residual stress placed on the steel during production. And so this is where the rubber meets the road as far as manufacturing an AK spec barrel is concerned. If high quality, clean, pollutant free steel is used, and the proper infrastructure is in place for pre-production material selection, production, and post production stress relief via heat treating etc., it’s true that very good button rifled barrels are achievable. All of these things are harder to achieve in a small scale facility. Where the hammer forger has clear advantage is three-fold. First, the capital for setting up a hammer forging facility is likely to be in place just by virtue of the costs involved in buying a forge. Secondly, with the capital to afford a hammer forge, one can use the capabilities inherent in hammer forging to bolster profits, pay for start up costs, and offset material costs by production of end items outside the scope of firearms. Producing parts for the automotive industry for example, is common practice for producers of hammer forged barrels. Using the profits garnered from industry outside the firearms business to pay for infrastructure, employ skilled metallurgists and to enable oneself to afford quality raw materials is just good business sense. An age old phrase to apply here is: "It takes money to make money”. Not to mention the fact that hammer forging barrels in bulk (as in millions) is cheap to do once setup. And thirdly, hammer forgers are able to make better barrels due to the precise machining afforded by a quality forge. The twist rate of rifling must be absolutely precise as minute changes count in large ways and hammer forging produces excellent twist rate by nature. With the use of precision mandrels fantastic twist rate is innate. And hammer forged barrels are naturally harder and require less post stress relief as the steel is compressed and hardened in part by the hammers pounding the steel around the mandrel.

Modern Russian small arms plants rely on Austrian hammer forging technology that is generally considered some of the best hammer forging technology available to date, generating rifles on an industrial scale for the Russian military and also the private sector. The Russians not only hammer forge barrels using advanced forging equipment, the mandrels they use forms the chamber at the same time they form the rifling. And when considering the skill involved in chrome plating the bore of a rifle Bill offered his qualified opinion as a designer of armaments and small arms. The Russians are entirely precise. The adherence is admirable and the density is very impressive. The Russians have raised chrome plating to an art form. We in the west can do the same, but do we? The uncomfortable answer to that question is probably not. The Russian mindset is one of being good enough. And they are very good at good enough."

[Czarnowidz]

Moge tez potem rozbudowac temat o jakies podstawowe przeliczenia, np wytrzymalosci luf czy obliczanie wymiarow tlocznika jakby ktos chcial

Bardzo bym prosił.

Interesuje mnie również wszystko co związane z bruzdowaniem elektrochemicznym. Składy płynów obróbkowych, parametry obróbki czyli prędkość posuwu, amperaż i napięcie, wydatek płynu obróbkowego, odstęp pomiędzy elektrodą a materiałem itp. Fajnie by też było zobaczyć jakiś film z produkcji.

Ma może jeszcze ktoś informacje z jakich stali produkowano w naszym kraju lufy pistoletowe?

[Jacek1]

Sodick takie rzeczy robi.
https://www.youtube.com/watch?v=XtQv733MJ3k

Ta technologia ma sens tylko przy produkcji masowej, inaczej to zawracanie sobie głowy przy lufach (mały zysk z obróbki).


Lufy w Polsce są niegodne nazwy, nie bez powodu w Polsce nie jest bity CIP, nie bez powodu w Polsce są normy zakładowe, a nie normy.
Materiał najlepiej stale chromowe o twardości 19-23hrc. Tylko się to strasznie obrabia, narzędzi dużo zjada. No to się robi z utwardzonych czarnych.

[ss100]

wskaż moment kiedy ta drutówka bruzduje lufę, no a co z lufami w P99? - je zdaję się u nas robią...

[waliza]

U nas lufy robi się obkuwaniem i chyba tylko obkuwaniem i to od dawna. Na maszynach steyra. Nie jestem pewien ale chyba tylko wiatrówki miały jeszcze gwinty robione tłocznikiem. Jako ostatnie.

[Uriasz]

U nas lufy robi się obkuwaniem i chyba tylko obkuwaniem i to od dawna. Na maszynach steyra.

Jeśli na maszynach Steyra to najpewniej od pierwszej połowy lat 70tych, bo wowczas nasi kupili licencje na sztucery mannlichera (co bylo raczej przykrywką bo za duzo tych sztucerow nie zrobili) i maszyny do ich produkcji.

[ss100]

Z tymi sztucerami to coś mi się wydaje że było na odwrót - produkowali dla steyera zestawy części (mozliwe że i nimi spłacali maszyny) ale steyer też się nie chwalił kto jest dostawcą częsci- jeszcze kilka lat w tył można było kupić zestaw sztucerowy, z lufą lub bez.
Trawione elektrochemicznie to do PK w Cegielskim były, ciekawe jakie teraz w Tarnowie stosują - bo z opisów w gazetach to teraz tylko się dowiesz że coś jest z kutego amelinium pokryte teniferową powłoką a plastykowe części ze spec poliamidu ( po angielsku oczywiście) hehe

[dexter 1990]

Jak się robiło lufy systemu Gerlicha?

[maziek]

Znaczy do ura? One się czymś różniły od "normalnych"?

[dexter 1990]

Pierwsze słyszę, żeby Ur miał taką lufę. Ur miał chyba "zwykłą". Ale mogę się mylić.

Co miał Ur to inna sprawa bo w sumie uciąć sobie nic nie dam. Interesuje mnie jednak jak lufy sys Gerlicha wykonywano (nie wnikam w czym one były stosowane ). Chodzi mi o tą klasyczną, stożkową na całej długości formę, nie o te ze stożkami przejściowymi.