The ASTM defines a number of alloy standards with a numbering scheme[4] for easy reference.
Grade 1-4 are unalloyed and considered commercially pure or "CP". Generally the tensile and yield strength goes up with grade number for these "pure" grades. The difference in their physical properties is primarily due to the quantity of interstitial elements. They are used for corrosion resistance applications where cost and ease of fabrication and welding are important.
Grade 5, also known as Ti6Al4V, Ti-6Al-4V or Ti 6-4, is the most commonly used alloy. It has a chemical composition of 6% aluminium, 4% vanadium, 0.25% (maximum) iron, 0.2% (maximum) oxygen, and the remainder titanium.[5] It is significantly stronger than commercially pure titanium while having the same stiffness and thermal properties (excluding thermal conductivity, which is about 60% lower in Grade 5 Ti than in CP Ti).[6] Among its many advantages, it is heat treatable. This grade is an excellent combination of strength, corrosion resistance, weld and fabricability. Consequently, it is used extensively in Aerospace, Medical, Marine, and Chemical Processing[7] E.g.internal combustion engine connecting rods and surgical implants.[5] Generally, it is used in applications up to 400 degrees Celsius.
It has a density of roughly 4420 kg/m3, Young's modulus of 110 GPa, and tensile strength of 1000 MPa.[8] By comparison, annealed type 316 stainless steel has a density of 8000 kg/m3, modulus of 193 GPa, and tensile strength of only 570 MPa.[9] And tempered 6061 aluminium alloy has 2700 kg/m3, 69 GPa, and 310 MPa, respectively.[10]
Grade 6 contains 5% aluminium and 2.5% tin. It is also known as Ti-5Al-2.5Sn. This alloy is used in airframes and jet engines due to its good weldability, stability and strength at elevated temperatures.[citation needed]
Grade 7 contains 0.12 to 0.25% palladium. This grade is similar to Grade 2. The small quantity of palladium added gives it enhanced crevice corrosion resistance at low temperatures and high pH.[11]
Grade 7H is identical to Grade 7 with enhanced corrosion resistance.[12]
Grade 9 contains 3.0% aluminium and 2.5% vanadium. This grade is a compromise between the ease of welding and manufacturing of the "pure" grades and the high strength of Grade 5. It is commonly used in aircraft tubing for hydraulics and in athletic equipment.
Grade 11 contains 0.12 to 0.25% palladium. This grade has enhanced corrosion resistance.[13]
Grade 12 contains 0.3% molybdenum and 0.8% nickel.[14]
Grades 13, 14, and 15 all contain 0.5% nickel and 0.05% ruthenium.
Grade 16 contains 0.04 to 0.08% palladium. This grade has enhanced corrosion resistance.
Grade 16H contains 0.04 to 0.08% palladium.
Grade 17 contains 0.04 to 0.08% palladium. This grade has enhanced corrosion resistance.[citation needed]
Grade 18 contains 3% aluminium, 2.5% vanadium and 0.04 to 0.08% palladium. This grade is identical to Grade 9 in terms of mechanical characteristics. The added palladium gives it increased corrosion resistance.[citation needed]
Grade 19 contains 3% aluminium, 8% vanadium, 6% chromium, 4% zirconium, and 4% molybdenum.
Grade 20 contains 3% aluminium, 8% vanadium, 6% chromium, 4% zirconium, 4% molybdenum and 0.04% to 0.08% palladium.
Grade 21 contains 15% molybdenum, 3% aluminium, 2.7% niobium, and 0.25% silicon.
Grade 23 contains 6% aluminium, 4% vanadium, 0.13% (maximum) Oxygen. Improved ductility and fracture toughness with some reduction in strength..[15]
Grade 24 contains 6% aluminium, 4% vanadium and 0.04% to 0.08% palladium.
Grade 25 contains 6% aluminium, 4% vanadium and 0.3% to 0.8% nickel and 0.04% to 0.08% palladium.
Grades 26, 26H, and 27 all contain 0.08 to 0.14% ruthenium.
Grade 28 contains 3% aluminium, 2.5% vanadium and 0.08 to 0.14% ruthenium.
Grade 29 contains 6% aluminium, 4% vanadium and 0.08 to 0.14% ruthenium.
Grades 30 and 31 contain 0.3% cobalt and 0.05% palladium.
Grade 32 contains 5% aluminium, 1% tin, 1% zirconium, 1% vanadium, and 0.8% molybdenum.
Grades 33 and 34 contain 0.4% nickel, 0.015% palladium, 0.025% ruthenium, and 0.15% chromium .[citation needed]
Grade 35 contains 4.5% aluminium, 2% molybdenum, 1.6% vanadium, 0.5% iron, and 0.3% silicon.
Grade 36 contains 45% niobium.
Grade 37 contains 1.5% aluminium.
Grade 38 contains 4% aluminium, 2.5% vanadium, and 1.5% iron. This grade was developed in the 1990s for use as an armor plating. The iron reduces the amount of Vanadium needed as a beta stabilizer. Its mechanical properties are very similar to Grade 5, but has good cold workability similar to grade 9.[16]
Kaynak: Wikipedia.
Mesleğim gereği titanyumun ilk beş grade'i ile çalışma fırsatım oldu. ve daha yukarıdaki listede bulunmayan bazı firmaların kullandıkları alaşımlarda var.
Titanyumun saf hali diyebileceğimiz grade 1 ve grade 2 o kadar yumuşaktırki elinizle bile 3mm lik bir bıçakta kullanılmış namluyu rahatlıkla ikiye katlayabilirsiniz. içersine eklenen vanadium ve aluminium ile sertliği arttırılsada çeşitli işlemlerden geçerek farklı sertlik dereceleri elde edilir titanyumda.
tıbbi amaçlı, inert bir malzeme olduğundan implant olarak kullanım yeri bulur ancak cerrahi aletlerde birkaç pens dışında kendisine yer bulamaz titanyum. Ki Neşterler bile 420 çelikten imal edilmektedir.
Şimdi yukarıdaki listede hangi titanyum tercih edilir? hangisi doğru tercihdir? hangi alaşımdan olmasını dilersiniz bıçağın?
Birazcık(!) malzeme bilgisi olan arkadaşlarımız işte o birazcık bilgileriyle çeliği tercih ederler. Evet ayrıca ülkemizde bulabilecekleri alaşımlarda sınırlıdır ama yinede hepsini bulsalar da tercihlerini yine çelikten yana kullanacaklardır şüphesiz bu Birazcık bilgiyle.
Ha evet benimde Birazcık malzeme bilgim var ve titanyum elbette çeliğe göre daha hafif ve korozyona daha dayanıklı bundan yola çıkarak, cam da çeliğe göre daha hafif ve korozyona daha dayanıklı ancak bıçak yapımında kullanılmamasının aynı olmasada benzer sebepleri var titanyum içinde geçerli olan. Belki arkadaşlar birazcıkda olsa biliyorlardır hangi çeliğin Tuzlu suda en fazla dayanacağını.
Saygılarımla
26 Yanıt
8873 Gösterim