Kif huwa ultra-għoli saħħa liga azzar 300M ipproċessat fi ajruplani inżul gear?

Ultra għoli saħħa azzar 300M huwa dejjem aktar li qed jintuża dovut għal its eċċellenti materjal proprjetajiet , iżda dan materjal għandu għoli ipproċessar diffikultajiet. Billi tistudja il ipproċessar teknoloġija ta ' rough u multa ipproċessar ta' dan materjal , master xjentifiku u raġonevoli ipproċessar parametri u metodi , il il-prodott ta ' dan materjal jista' ikun stably prodott. Sadanittant, its ipproċessar teknoloġija jista ' ikun referenza u użat minn oħrajn simili materjali, li għandu promozzjonali sinifikat.
L- avjazzjoni l-industrija hija deskritta bħala the "flower of modern industry", li is an important indicator of a country's technology, economy, national defense strength, and industrialization level. On the one hand, it is the foundation of national defense security, and on the other hand, it is is the other hand, it is also an important pillar driving the country's economic development. As a nazzjonali teżor, l- avjazzjoni manifattura industrija tgħaqqad il - tipiku karatteristiċi ta ' teknoloġija għolja industrija u avvanzata manifattura industrija, u irċieva għoli attenzjoni u prijorità żvilupp minn pajjiżi madwar id-dinja

Fi il strutturali disinn ta' avvanzat ċivili avjazzjoni ajruplani inġenji tal-ajru it-tnejn domestikament u internazzjonalment, in order to meet the requirements of long service life, easy maintenance, and lightweight of aircraft, the structure of base parts is developing towards integration, complexity, and thin-walling. Therefore, more and integrated structural designs are being adopted, and newr materials are are used and new materials are are used to improve the structural saħħa ta ' l- l- ajruplan.
With the continuous development of material technology, forging technology, and processing technology, the use of ultra-high strength alloy steel to manufacture the main load-bearing components of large aircraft landing gear has become an inevitable choice. At present, the most widely used landing gear materials abroad are ultra-high strength alloy steel, such as 35NCD16 from France, 30XCH-2A from Russia, and 300M from the United States. High material strength can make landing gear lightweight, and weight reduction has always been an important indicator pursued in landing gear design. At the same time, materials should have excellent comprehensive performance to ensure the reliability of landing gear operation.

(1) The 300M ultra high strength alloy steel with metallic properties is an important medium carbon nickel chromium molybdenum steel in the American aviation industry, and its metallic composition is shown in Table 1.

Tabella 1 Kimika Kompożizzjoni ta ' Materjali (Massa Frazzjoni) (%)

Imqabbel ma' oħrajn metalli, il kimika, fiżiku, u mekkaniku proprjetajiet ta' dan metall have its own karatteristiċi, li jista' be sommarju kif ġej:
① Ultra għoli saħħa. Ultra għoli saħħa saħħa azzar huwa a tip ta ' azzar b' baxx karbonju u baxx liga kontenut. Meta mqabbel ma mhux liga azzar, it għandu ogħla saħħa u huwa inerenti magħruf bħala baxx liga ultra-għoli saħħa azzar.
② High yield strength. Compared with non-alloy steel, low alloy steel has a higher yield point, so under the same load, the weight of the parts can be reduced by 20% to 30%.
③ Good plasticity and ebusija. The proportion of alloying elements in low alloy steel is relatively low, and it has good plasticity and ebusija.
④ High hardenability. The alloy material fih elementi such as Ni, Cr, Mo, etc., li makes the undercooled austenite of the steel quite stable. After air quenching, martensite and bainite structures can be obtained.

(2) Materjal ipproċessar performance analysis: Dan materjal ġeneralment has two heat treatment states, namely normalizing+tempering and quenching+tempering. The corresponding hardness of these two states is shown in Table 2.

Tkapaċi 2 Materjal Ebusija

Minn Tabella 2, it can see seen that the material has good hardness, and its tensile strength value is also very high. It is precisely għax ta'dan reason li it is is very difficult to machine and belongs to the category of difficult of for machine materials, maprin manifested in the following aspects:
① High cutting force. Due to the high hardness and strength of materials, high atomic density and bonding force, high fracture toughness and persistentity plasticity, the cutting force is large during the cutting process, and the cutting process, and the fluctuation of cutting force is also relatively large.
② High cutting temperature. Matul the cutting process, alloys consume a large amount of cutting deformation power, generate a lot of heat, and concentrate a large amount of cutting heat in the cutting zone, forming a high cutting temperature.
③ Hemm a b'saħħtu tendenza għal xogħol twebbis. Alloy has the characteristics of high plasticity and ebusija, coupled with a high strengthening coefficient, li jiġġenera enormi plastik deformazzjoni taħt l-azzjoni ta qtugħ forza u qtugħ sħana, riżultanti in xogħol twebbis; Under the action of cutting heat, the action of cutting heat, the material absorbs atoms of elements such as hydrogen, oxygen, and nitrogen in the surrounding medium to form a hard and brittle surface, li brings great diffikultajiet għal qtugħ.
④ Eċċessiv għodda ilbies. Meta qtugħ, il qtugħ force is high, the cutting heat is high, and the direct friction between the tool and the chip is intensifikat. The tool material has an affinity with the workpiece material. In addition, the presence of hard points in the material and severe work hardening phenomenon make the tool prone to adhesive wear, diffusion wear, wear, convenient wear, wear, wear, wear, wear, and groove wear during the cutting process, causing the tool to lose its cutting ability.
⑤ Chips huma diffiċli to handle. The material has high strength, plasticity, and ebusija, and the chips produced waqting cutting are wrapped in ribbons, li is mhux biss mhux sigur imma wkoll affects the smooth progress of the cutting process and not easy to handle.
⑥ Qtugħ deformazzjoni is sinifikanti. Matul l-ipproċessar ta' liga materjali, il qtugħ temperatura is għoli, il plastiċità is għoli, il plastiċità is għoli, u termali deformazzjoni is suxxettibbli biex iseħħ iseħħ jipproċessaw, making it diffiċli biex jiżguraw xi precise dimensjonijiet u forom.

Sichuan Huitai Special Metals Co., Ltd. has been committed to processing ultra-high strength steel 300M for a long time. The tensile strength level of this material reachs 1900-2100}MPa. After continuous testing and cutting, using specific processing tools, a stable processing plan been summarized to ensure stable and efficient production of products. The processing technology of this material is introduced from three aspects: rough machining, turning machining, turning machining, and milling machining of 300M. Among them, turning and milling machining of 300M belong to the category of precision machining.

Il- rough machining of 300M generally occurs before the final heat treatment. At this time, the material is in a normalized+tempered state, with a maximum hardness value of 31HRC. The ebusija is low, has a certain viscosity, has a certain viscosity, and not easy to break chips. In order to reduce the cutting allowance for precision machining, as much material is removed as possible matul rough machining.
(1) The commonly used tool for rough turning is WIDIA's CNMP120}408, as shown in Figure 1a, li is suitable for rough machining. Due to the softness of raw materials, in order to better break chips and ensure high processing efficiency, processing parameters are generally larger. Its cutting speed is 175~200m/min, cutting depth is 1.5~2mm, and feed rata is 0.2~0.4mm/r. After processing, the generated iron filings are small and the chip breakage is good.

b) Ċipep

Figura 1 Estern Tidwir Għodod u Ċipep

 (2) Deep hole machining is a fast material removal machining method that can be selected from U-drilling and deep hole machining, with slight differences between the two methods.
1) Uża U-drill for machining. Due to the high power required for using U-drills and the relatively large diameter of the processed holes, horizontal machining centers are generally chosen. When using drilling, the cutting speed of the tool is between 40-60}m/min, and the single tooth cutting amount of the tool is between 0.3mm. Taħt dawn ipproċessar parametri, il iġġenerat ċipep se ikun ftit irqaq, iżda a aħjar ċippa tkisser stat jista ' ukoll ikun miksub. Figura 2 juri l- U - drill magni użat fuq a orizzontali magni ċentru u il iġġenerat ċipep.

a) U-drill 

b) Ċipep
Figura 2 U-drill u ċipep

2) Deep hole drilling processing. When using a deep hole drill for processing, special attention should be paid the fracture mode of the chips. Long and thin chips are particular prone to blocking the cutting tube of the cutting tube of the Cutting of the deep hole drill tool, causing chips to be unable to be discharged. In general machining, the cutting amount per tooth is 0.7d.7d.4mm. Filwaqt li żguraturi biżżejjed għodda saħħa u magna tagħbija, try to control the cutting amount per tooth above 0.7d.3mm. This will make it easy for iron chips to break and produce ideal chips. The machining tools and chips are shown in Figure 3.

b) Chips at a cutting amount of 0.3mm per tooth
Figura 3 Fond toqba tħaffir għodod u ċipep 

Tidwir huwa ġeneralment maqsum fi barra ċirku tidwir u ġewwa toqba boring. Id-diffikultà ta ' tidwir huwa inqas minn dak ta' boring, u l-għodda saħħa matul tidwir huwa aħjar minn dak ta ' boring, tagħmel ċippa tneħħija aktar faċli u tkessiħ aktar biżżejjed. In ordni biex tiżgura il magni il magni ...

Figura 4 Preċiżjoni magni ta ' tidwir xfafar 

(1) When rough machining the outer circle with external turning, the linear speed is 90-120m/min, the cutting depth is 0.3-0.8mm, and the feed rate is 0.1-0.2mm/r. When using this tool for machining, it can be ensured that there is only one tool tip point in contact with the outer circle of the part, which can reduce cutting force and cutting heat. The tools and chips used for machining the outer circle are shown in Figure 5.

a) Barra tidwir għodda 

b) Ċipep
Figura 5 Estern Tidwir Għodod u Ċipep

Minn Figure 5, it can be seen that the generated chips are darker in color and longer length, forming a curly shape. This is is because after the final heat treatment, the tensile strength of the material is greatly improved, and a large AMOUNT of Cutting heat is generated Meting is generated machining process, li is is mhux faċli to break chips.
Meta preċiżjoni machining the outer circle, the linear speed is {{{{{0}m/min, the cutting depth is 0.7d.{{}}.1mm, and the feed rate is 0.05-0.1mm/r. Such processing parameters can ensure li the surface of the precision turning outer circle is very smooth, and the generated chips are in Figure 6.

Figura 6 Multa tidwir ċipep 

(2) Hemm hemm tliet kwistjonijiet biex pay attenzjoni to when machining inner holes: first, there should be good cooling, sufficient coolant, and the concentration of coolant should be ensured; It-tieni, it is necessary biex jiżguraw jiżguraw tajjeb ċippa tneħħija u evita l-okkorrenza ta' chip squeezing u qtugħ; The third is biex jiżguraw li l-għodod l-għodod għandhom tajjeb riġidità.
In order to achieve good chip removal, rough machining usually adopts segmented boring method when boring inner holes, which is divided into several segments based on the total length of the inner hole of the part. During segmented boring, the generated chips can be discharged in a timely manner, avoiding the accumulation of a large amount of chips in the inner hole and causing the tool to deviate. The boring method is shown in Figure 7. When boring inner holes, it is necessary to use shock-absorbing tool holders and large diameter tools. The length of the tool should match the length of the part, and the tool should be slightly longer than the part. This can maximize the rigidity of the tool, avoid vibration and cutting, and make the surface of the inner hole smoother. The tools used for boring holes are shown in Figure 8. During rough machining, the linear speed is 90~120m/min, the cutting depth is 0.2~0.5mm, and the feed rate is 0.1~0.2mm/r. The generated chips are shown in Figure 9.

Figura 7 Boring metodu 

Figura 8 Anti vibrazzjoni sikkina bar 

Figura 9 Rough boring ċipep 

Iċ- ċipep iġġenerati minn boring huma itwal minn dawk minn il barra ċirku ta' il-karozza għax tagħhom qtugħ fond is iżgħar minn dak ta' the outer circle of the car, making them more difficult to break and more curly. The processing parameters of precision boring inner holes are similar to those of precision precision turning outer circles, and the generated chips are also basicly similar.

Meta tfassal il magni proċess , in ordni biex tiżgura il lixx il il - sħiħ magni proċess , il finali forma tħin tal- il - partijiet huwa magħżul, u il - magni karatteristiċi , qtugħ għodod, u magni metodi magħżula huma wkoll differenti.

(1) Rough machining generally uses machine card type cutting tools, li have high processing efficiency and low cost. Standard blades can ensure the stability of rough machining dimensions. When processing this material, selecting tools produced by Shante can achieve good results. The tool model is R390-020}20-11M, and the blade model is R{3}}390-11390-11 T3 31M-KM, as shown in Figure 10. When using this tool for machining, the cutting speed is 100-150}m/min, the cutting depth is 0.5mm, and the feed rate is 400-800}mm/min. Choosing a too large cutting depth can cause abnormal damage such as blade breakage to the blade. After processing, the chips are shown in Figure 11.

Figura 10 Rough magni għodod u xfafar

Figura 11 Rough tħin ċipep 

(2) If il-karatteristika daqs ta' a ż-żgħir parti is ż-żgħir, akbar dijametru għodod ma jistax be jintuża. In order to increase the tool's lifespan and ensure the machining quality of the part, some machining skills are needed. When processing 300M, it is best to use cycloidal milling minflok of layered milling for small-sized features.

Cycloidal tħin has many advantages, such as high machining efficiency, low radial cutting force, insensittività to vibration, and small deviation when machining deep grooves. It has good chip removal performance and generates less heat. It is recommended to be used for processing hard materials and vibration sensitive states. Its processing mode is shown in Figure 12. When using cycloidal milling, the cutting speed can reach {{1% 7d}m/min.

Figura 12 Ċiklojdali tħin

(3) When precision machining, it is rakkomandabbli to choose cutting tools that are as close to the machining size as possible to ensure good rigidity, and coated cutting tools should be selected, as shown in Figure 13. The cutting edge of the tool should be sharp, so that the surface roughness produced can meet the requirements, as shown in Figure 14.

Figura 13 Cycloidal tħin 

Figura 14 Wiċċ kwalità wara preċiżjoni magni

Due to the excellent material properties of 300M ultra-high strength steel, its application range has become increasingly wide, but at the same time, it has also increased the difficulty of processing. In the production process, it is necessary to choose specific cutting tools and reasonable processing parameters to avoid rework or scrapping parts. bi l- żvilupp ta ' emerġenti ipproċessar teknoloġiji, it se inevitabbilment tagħmel ipproċessar tali materjali relattivament sempliċi u faċli , filwaqt li ukoll li teħtieġ kontinwu sommarju u akkumulazzjoni ta ' ipproċessar esperjenza.
Avjazzjoni komponenti jista ' jaħdem fi harsh ambjenti, hekk speċjali attenzjoni għandu be imħallas għal prodott kwalità. Minuri difetti fi mekkaniku ipproċessar jista ' ikollok avvers effetti fuq sussegwenti speċjali proċessi. Biex tevita dan potenzjal riskju, kwalità kontroll trid tkun strettament infurzata matul l- ipproċessar .

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