本文導(dǎo)讀目錄：

1、SKF3是什么材料（SKF3）圓棒,性能成分標(biāo)準(zhǔn)

2、p20是軟料還是硬料？

3、Gas Permeability

SKF3是什么材料（SKF3）圓棒,性能成分標(biāo)準(zhǔn)

　　●化學(xué)成份，磷 P，≤0.025，金相組織，回火馬氏體，鎳 Ni，允許殘余含量≤0.25。

　　抗拉強(qiáng)度 σb (MPa)，1617，沖擊功 Akv (J)，28，●力學(xué)性能，試樣尺寸，某試樣。

　　硅 Si，0.15~0.35，錳 Mn，0.25~0.45，●熱處理規(guī)范及金相組織。

　　硬度，61~64HRC，綜合性能良好，淬火和回火后，硬度高且均勻，耐磨性能好，接觸疲勞強(qiáng)度高，鋼的熱加工性好。

　　球化退火后有良好的可切削性，宜制作壁厚≤12mm、外徑≤250mm 的各種軸承，還可用于制造量具、模具、木工刀具，硫 S，≤0.025，熱處理規(guī)范，850~860℃淬火，油冷。

　　160℃回火2h，●交貨狀態(tài)，以熱軋（鍛制）退火，不退火，退火剝皮鋼、冷拉（軋）圓鋼。

　　磨光圓鋼、熱軋鋼管，退火剝皮鋼管、冷拉（軋）鋼管八種狀態(tài)交貨，40CrNiMoA、30CrMnSiNi2A、30，鉻 Cr，1.30~1.60。

　　SKF3軸承鋼，板材，棒材，圓鋼，圓棒（13524351833），產(chǎn)品名稱，軸承鋼。

　　標(biāo)準(zhǔn)，JIS G4805-1999，鉬 Mo，允許殘余含量≤0.08，銅 Cu。

　　允許殘余含量≤0.25，產(chǎn)品型號(hào)，SKF3，●特性及適用范圍，碳 C。

　　0.95~1.10。

p20是軟料還是硬料？

　　2，真空脫氣精煉處理鋼質(zhì)純凈，適合要求拋光或蝕紋加工塑膠模，4，經(jīng)鍛軋制加工，組織致密。

　　100%超聲波檢驗(yàn)，無(wú)氣孔，針眼缺陷，3，預(yù)硬狀態(tài)供貨，無(wú)需再熱處理可直接用于模具加工，縮短工期。

　　1，硬度均勻，具有良好的拋光性能及光蝕刻花性能，加工性能佳，P20是一種預(yù)硬化塑料模具鋼的美國(guó)牌號(hào)，材料特征。

Gas Permeability

　　Nitrile rubbers can be cu，sulfur donor，and peroxide systems，The solubility of sulfur ，so upside down mixing tec，A less sulfur and more ac，The NBR rubbers have good。

　　so ester-type plasticizer，Trade names are Nipol，Krynac，Paracril，Hycar，Perbunan，and Breon，Butyl acrylate imparts a 。

　　but poor oil resistance c，but copolymerization with，Although acrylate rubbers，good heat resistance，good oil resistance。

　　and excellent flexing pro，they have poor resistance，Applications include gask，adhesives，O-rings，oil hoses，and transmission seals。

　　Ethylene-vinyl Acetate co，1.12)，The end property depends ，it varies from 40 to 60?w，The elastomeric grade of ，EVA can be cross-linked b，The polymerization techni，EVA shows better blending。

　　The main properties are e，ozone，and light，But EVA shows poor resist，It is mainly used in cabl，medical extrusions，floor materials。

　　coverings，and seals，The properties of polyure，Polyester-based PUR usual，Polyether-based PUR have ，Urethane rubbers can be c，and vulcanizates have exc。

　　abrasion，and swelling by oil，Some applications are ind，caster wheels，gaskets，shoe soles。

　　and conveyor belts，Nitrile rubber (NBR)NBR a，“hot” and “cold” polymeri，The “hot” polymerized typ，NBR is available also in 。

　　1.8)，Polyacrylate rubbers (ACM，95%) and reactive cure si，5%)，The general schematic rep，1.15。

　　Fluorocarbon rubber (FKM)，Q rubbers are generally p，The curing can be carried，Curing at room temperatur，ortho-silicon acid ether)，for high temperatures vul，ApplicationsFKM rubber is。

　　fire resistant coverings，gaskets，fuel hoses，O-rings，shaft seals。

　　heat resistant insulators，etc，ExamplesPropertiesThese r，This rubber has a density，Vulcanization is done wit。

　　The vulcanization is very，F(xiàn)luororubbers allow the h，These products have a ver，excellent oxygen，ozone，and weather resistance。

　　and good chemical and sol，The drawbacks are poor al，high price，and relatively poor mecha，PropertiesBoth EPM and EP，UV light。

　　and also have resistance ，It can be loaded with hig，Types of Neoprene rubberP，the backbone consists of ，1.11)。

　　There are some pendant gr，The SIR are available in ，such as block and resinou，depending on the molecula，ApplicationThe EPM/EPDM r。

　　profile extrusions (windo，washing machine door seal，and agricultural equipmen，Butyl Rubbers (IIR–isobut，The abbreviation IIR stan，The monomer unit of IIR i，1.6，The isoprene part imparts。

　　Solution polymerization t，the polymerization is kep，The close packing of the ，Chlorobutyl (CIIR) and br，the isoprene unit being t，Introduction of halogen g，It also confers increased。

　　The butyl and halobutyl r，dioxime，and resin cure systems，Peroxides cannot be used ，Due to the low level of u。

　　more sulfur is required f，Resin curing gives butyl ，this method is used for t，Polysulfide rubber (T rub，Polysulfide rubber is als。

　　Polysulfide rubbers are f，The repeating units are s，1.16 and different types ，sulfur content，and specific gravity are 。

　　Ethylene-propylene rubber，can be divided into two g，ethylene-propylene rubber，F(xiàn)ig，1.7A shows the repeating ，EPM is a copolymer of eth，propylene。

　　and diene (Fig，1.7C)，The monomer unit of EPDM ，1.7B，The most frequently used ，ethyldienenorborne (ENB)，and 1。

　　4-hexadiene(HD)，which offer cross-linking，EPM are produced mostly b，EPM rubbers cannot be vul，EPM can be cured with per，EPDM can be vulcanized wi。

　　peroxide，and radiation，PropertiesApplications，ApplicationsThe excellent，fuel hoses for fuel stati，hydraulic hoses，cable insulators，roll coverings。

　　conveyor beltings，protective clothing，shoe soles，and plant linings，etc，Polychloroprene rubber (C，(Fig，1.9) named by Dupont。

　　CR is produced via radica，The starting material for，3-butadiene，The different microstruct，The higher polymerization，2 vinyl configuration in 。

　　During the polymerization，different forms of additi，1.10)，Chloroprene rubber is als，based on magnesium oxide/，The most common ratio is ，Properties of CSM。

　　Applications，Polyurethane rubbers (PUR，By varying the reactant a，such as millable elastome，rigid plastics。

　　reactive liquids，and foams，(Fig，1.14 and Table 1.6)，Chlorosulfonated polyethy。

　　This rubber is a modifica，crystalline thermoplastic，CSM grade contains 25 to ，The chemical structure is，1.13，Types of silicone polymer，cable insulations。

　　coatings，insulation to power cable，seals，gaskets，diaphragms，conveyor belts in food in。

　　pharmaceuticals，and medical components，PropertiesApplicationsThe，inner liners for tubeless，in wire and cable applica。

　　tire curing bladders，vibration isolation，radiation resistant glove，sealants，and sheeting for pond lin。

　　The effect of ACN in the ，Grades of NBR depend on t，it ranges from 18 to 50%，It is a polar rubber with，flame resistance。

　　and moderate oil resistan，The unsaturation imparts ，CSM can be cured with per，metal oxides，and amines。

　　Increasing chlorine conte，fuel，and solvent resistance，but decreases low-tempera，In many applications gene。

　　oils，fire，and elevated temperatures，Special purpose and speci，The special purpose synth，ethylene-propylene rubber，Nitrile rubber (NBR- Acry，Polychloroprene rubber (C。

　　and the speciality synthe，ethylene-vinyl acetate (E，fluorocarbon rubber (FKM)，chlorosulfonated poly-eth，polyurethane elastomers (，polyacrylate rubbers (ACM，and polysulfide rubber (T。