Magnesium vs. Aluminum vs. steel

[bernie]

May mga bagong pedals na yari sa Magnesium, pati sa suspension fork? Alin ba ang mas matibay o reliable? Magnesium, steel o aluminyo? Kailan ba dapat magnesium o aluminum o bakal ang isang pyesa?

[Overclocker]

Alumininum FATIGUES by merely using it, even if you don't exceed its elastic limit. i.e. that aluminum handlebar gradually deteriorates even if you don't apply enough force to bend it.

Steel doesn't have this problem, unfortunately it's heavy...

[jr]

Here is the article I found regards comparison between aluminum and magnesium on fork and frame build. I did not put steel cause mostly not excess in bike setup now days (for MTB bikes).

Magnesium - An excellent lightweight material that can be machined from billet or die-cast. A Magnesium die-cast lower leg is the best manufacturing method and material to satisfy the structural and precision machine requirements on a suspension fork. Magnesium has excellent vibration damping characteristics and is 34% lighter than aluminum and 77% lighter than steel.

6061-T6 Aluminum - This is the most versatile of the heat treatable aluminum alloys. It has most of the good qualities of aluminum and it offers a wide range of mechanical properties and corrosion resistance. It can be fabricated by many of the commonly used techniques and is usually offered in T6 temper for high-strength applications.

7075-T6 Aluminum - 7075-T6 is the strongest and most expensive aluminum alloy that is used for structural and highly stressed components.

Hard Anodize - A dense wear-resistant anodic surface coating on Aluminum parts that has 50% buildup and 50% penetration into the material. In general, hard anodizing is applied following the military specification MIL-A-8625 Type III, Class 1 for non-dyed, or Class 2 for dyed applications. All Hard Anodized FOX products have proprietary post surface treatments that provide ultra low friction and wear to the mating components.

Titanium - A material with a high strength to weight ratio, that when alloyed (combined) with other Elements can provide the required functional properties for such parts as springs, shafts and fasteners. It is one of the most abundant material elements on earth, but due to the stringent manufacturing standards and high processing costs, the raw material is quite expensive. Unlike steel, and similar to aluminum, Titanium has a finite fatigue life. Density: .162 Lb/Cu-In, Melting Point 3100 Deg

[bernie]

Very Informative dre, i will print that.

[warlock^_^]

I got something about steel (Steel frame kasi ako hehe BIAS!)

www.reynoldsusa.com/tubing/tubing.html

Comparative Mechanical Properties of Commonly Used Cycle Tube Materials


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For the technically curious, you may be interested in details of useful properties for materials found on bikes. The tables of figures below compare:


Reynolds 853 Air Hardened Steel

Reynolds 531 (non heat-treated) Manganese-Moly steel

Typical Aluminum 7005 series

Typical Titanium 3/2.5

This page was done independently by Reynolds staff, but VeloNews' 1994 Metallurgy for Cyclists series by Scott Nicol provides more detail on the advantages and disadvantages of materials. (The articles were done before Reynolds 853 was launched).
Definitions

Strength (UTS): This indicates force per unit area required, in thousands of lbs per square inch ("Ksi") tested by pulling apart the material until it fractures to find the Ultimate Tensile Strength. The higher the number, the more force that has to be applied to make it break.

Density: The weight of material in pounds per cubic inch of volume. The lower the number the lighter the weight of tube for a given volume.

Modulus: A measure of the stiffness of the material in Ksi, the higher the number the stiffer the material for a given volume.

0.2% Proof: As yield points of materials can occasionally be difficult to measure, this property is often used to give an indication of the stress at which the material will produce a permanent deformation in a tube set without causing actual fracture of the material. The higher the number, the higher the force the part can withstand before permanently deforming. The numbers are measured in Ksi.

Fatigue Limit: Defined as the stress at which failure will not occur after at least 10 Million cycles fatigue loading, and gives an idea of frame life. The higher the value the more stress is required to breach this threshold. Measured in Ksi.

Elongation: the amount the material stretches, before breaking, expressed as a percentage of the original length. Values lower than 5-7% would be considered brittle for bike frames.



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Now for the data, if you survived this far. The tables show both the actual values for the four materials, as well as being expressed as a percentage. So you can see that Titanium has a UTS only 53% of 853, but it is also 57% lighter. And when you have looked through all the numbers, note that frame design plays a crucial part in making use of these properties.

Designers can change the length of the butted sections, or wall thickness to save weight or reinforce joints. Or increase the diameter of the tubes for stiffness (but could add weight), or even choose a mix of these to increase the resiliency of the frame (and give a better ride). Extremely stiff frames don't necessarily mean rideable ones, and costs for materials are also an issue.



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Table 1: Typical Material Properties Relative to Reynolds 853
Reynolds Steel 853/ Reynolds Steel 531/Aluminum7005 series/ Titanium3/2.5 grade
UTS 100%/ 58% /26% /53%
Density 100% /100% /36% /57%
Modulus 100% /100% /36% /53%
0.2% Proof 100% /63% /30% /60%
Fatigue Limit 100% /61% /23% /63%
Elongation 100% /150% /120% /150%




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Table 2: Typical Material Properties of the Tube Materials above
Reynolds Steel 853 /Reynolds Steel 531 /Aluminum 7005 series /Titanium 3/2.5 grade

UTS Ksi: 190 /110 /49 /100
Density lbs/cubic in: 0.28 /0.28 /0.10 /0.16
Modulus Ksi: 29000 /29000 /10500 /15250
0.2% Proof Ksi: 150 /95 /45 /90
Fatigue Limit Ksi: 90/ 55 /21 /57
Elongation %: 10/ 15/ 12/ 15




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The question that Reynolds personnel are often asked is "What is the best material for a bike frame? ". As you can see, there are several things to consider, depending on your priorities and riding style.

It's your choice, but steel still offers a tremendously competitive package

[bernie]

Kasi naman kung tutuusin, steel talaga ang pinakamatibay sa lahat, yun nga lang bukod sa mabigat, ay na brain damaged na ang mgs siklista na kapag steel ang frame mabigat padyakan di ba?

Pero nung may karera sa Binan noon ng XC series, lintsak, ang nanalo, ang Batalya Bakal na malaki pa gulong, isang magtitinda ng dyaryo, olats ang pinakamalakas sa amin!

Nasa pumapadyak din although bike weight plays a lot in speed & climbing e kaso si Superman ang pumadyak, ayun na! ;D

[warlock^_^]

Yehey! may kampi na ako! Bernie bili ka rin ng steel framed MTB...or better yet, pa assemble ka using Columbus Steel or Tange. I heard may magaling na fabricator/welder na nagbubuo (OCW skilled worker daw) world class quality.

[bernie]

May batalya akong old model na Bridgestone Japan pa nga e, di ko lang alam ang model pero magaan naman siya, balak kong buuin pero di siya Disc Compatible, gagawin ko na lang rigid bike.