Which type of aluminium is used for cast Derailleur hangers?
01-17-20, 11:57 AM
#1
Junior Member
Thread Starter
Join Date: Jan 2020
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Which type of aluminium is used for cast Derailleur hangers?
Hi there,
Could you please offer me some assistance, I'm doing a school project and would like to know the specific type of aluminium or at least the series of aluminium mostly used in the manufacture of cast replaceable derailleur hangers most sites just state it as aluminium without giving a specific type, unlike the CNC variants which are sometimes listed as 6061 aluminium.
Many thanks in advance
Could you please offer me some assistance, I'm doing a school project and would like to know the specific type of aluminium or at least the series of aluminium mostly used in the manufacture of cast replaceable derailleur hangers most sites just state it as aluminium without giving a specific type, unlike the CNC variants which are sometimes listed as 6061 aluminium.
Many thanks in advance
01-17-20, 02:47 PM
#2
Senior Member
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times
in
723 Posts
The most common aluminum alloys used for casting are the 300 series alloys, with A380 being the most commonly specified. The300 series are composed of aluminum, silicon and copper or magnesium primarily.
It is likely that a simple part such as a derailleur hanger will be cast of A380.
https://diecasting.com/blog/2018/02/...uminum-alloys/
https://www.dynacast.com/en/knowledg...casting-metals
It is likely that a simple part such as a derailleur hanger will be cast of A380.
https://diecasting.com/blog/2018/02/...uminum-alloys/
https://www.dynacast.com/en/knowledg...casting-metals
Likes For dsbrantjr:
01-17-20, 03:13 PM
#3
Disco Infiltrator
Join Date: May 2013
Location: Folsom CA
Posts: 13,446
Bikes: Stormchaser, Paramount, Tilt, Samba tandem
Mentioned: 72 Post(s)
Tagged: 0 Thread(s)
Quoted: 3126 Post(s)
Liked 2,105 Times
in
1,369 Posts
Okay, but... aren’t they made from stock?
__________________
Genesis 49:16-17
Genesis 49:16-17
01-17-20, 04:22 PM
#5
Junior Member
Thread Starter
Join Date: Jan 2020
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
The most common aluminum alloys used for casting are the 300 series alloys, with A380 being the most commonly specified. The300 series are composed of aluminum, silicon and copper or magnesium primarily.
It is likely that a simple part such as a derailleur hanger will be cast of A380.
It is likely that a simple part such as a derailleur hanger will be cast of A380.
01-17-20, 04:28 PM
#6
Junior Member
Thread Starter
Join Date: Jan 2020
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I could also use your help with one more question. When looking at replaceable derailleur hangers manufactured by cold forging the material is given as 6061 aluminium. I know that for those made by CNC 6061-T651 is commonly used but which specific variant of 6061 is used for cold forging? I thought it would be 6061-O as it has good formability, however, it's a significantly weaker material than 6061-T651.
01-17-20, 04:42 PM
#7
Really Old Senior Member
I could also use your help with one more question. When looking at replaceable derailleur hangers manufactured by cold forging the material is given as 6061 aluminium. I know that for those made by CNC 6061-T651 is commonly used but which specific variant of 6061 is used for cold forging? I thought it would be 6061-O as it has good formability, however, it's a significantly weaker material than 6061-T651.
01-17-20, 05:04 PM
#8
Senior Member
Join Date: Feb 2012
Location: Rochester, NY
Posts: 18,071
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4199 Post(s)
Liked 3,852 Times
in
2,302 Posts
But stiffness is a nice aspect of hangers. Al has, unlike steel, a varying degree of stiffness due to alloys and treatments. And of course part geometry (cross sectional area being a biggie) can contribute to stiffer or stronger hangers. Or, more to the point, the same design choices can lead to a weak or flexy hanger. Andy
__________________
AndrewRStewart
AndrewRStewart
01-17-20, 05:57 PM
#9
Disco Infiltrator
Join Date: May 2013
Location: Folsom CA
Posts: 13,446
Bikes: Stormchaser, Paramount, Tilt, Samba tandem
Mentioned: 72 Post(s)
Tagged: 0 Thread(s)
Quoted: 3126 Post(s)
Liked 2,105 Times
in
1,369 Posts
So it turns out yes there are cast derailleur hangers. Huh. Seems like if you wanted to make something cheap it would be cheaper and just as good to stamp it out of steel
__________________
Genesis 49:16-17
Genesis 49:16-17
01-17-20, 06:58 PM
#10
Senior Member
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times
in
723 Posts
I could also use your help with one more question. When looking at replaceable derailleur hangers manufactured by cold forging the material is given as 6061 aluminium. I know that for those made by CNC 6061-T651 is commonly used but which specific variant of 6061 is used for cold forging? I thought it would be 6061-O as it has good formability, however, it's a significantly weaker material than 6061-T651.
https://www.engineersedge.com/aluminum_tempers.htm
Aluminum Alloy Heat Treatment Temper Designations
01-17-20, 07:01 PM
#11
Senior Member
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times
in
723 Posts
Well, the hangers which are integral to steel dropouts ARE stamped (or cast) out of steel, but they lack the mechanical "fuse" action of a weaker aluminum.hanger
01-17-20, 07:03 PM
#12
Full Member
EK987h,
Aluminum is heat treated after forging, and cold does not mean room temperature. In general cold forged means below any recrystallization temperature. The recrystallization temperature is ~750 F or so depending on the exact alloy and composition. So, to answer your question the part of concern would be forged, most likely, stamped in a die, then subsequently solution heat treated and aged to the T6 or T61 condition. Hope this helps with your project.
I find it somewhat hard to believe these would be cast, when today you can water jet or laser cut a blank, clean it up, drill necessary holes, thread as necessary and ship the part.
Just my couple of cents worth of thought.
Aluminum is heat treated after forging, and cold does not mean room temperature. In general cold forged means below any recrystallization temperature. The recrystallization temperature is ~750 F or so depending on the exact alloy and composition. So, to answer your question the part of concern would be forged, most likely, stamped in a die, then subsequently solution heat treated and aged to the T6 or T61 condition. Hope this helps with your project.
I find it somewhat hard to believe these would be cast, when today you can water jet or laser cut a blank, clean it up, drill necessary holes, thread as necessary and ship the part.
Just my couple of cents worth of thought.
01-17-20, 07:12 PM
#13
Senior Member
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,656
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2026 Post(s)
Likes: 0
Liked 1,096 Times
in
742 Posts
Yeah, from a cost standpoint a stamped steel hanger would be cheaper but it would also be too strong. You want a relatively weak hanger so it breaks first rather like a shear pin.
01-20-20, 05:49 PM
#15
Junior Member
Thread Starter
Join Date: Jan 2020
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
EK987h,
Aluminum is heat treated after forging, and cold does not mean room temperature. In general cold forged means below any recrystallization temperature. The recrystallization temperature is ~750 F or so depending on the exact alloy and composition. So, to answer your question the part of concern would be forged, most likely, stamped in a die, then subsequently solution heat treated and aged to the T6 or T61 condition. Hope this helps with your project.
I find it somewhat hard to believe these would be cast, when today you can water jet or laser cut a blank, clean it up, drill necessary holes, thread as necessary and ship the part.
Just my couple of cents worth of thought.
Aluminum is heat treated after forging, and cold does not mean room temperature. In general cold forged means below any recrystallization temperature. The recrystallization temperature is ~750 F or so depending on the exact alloy and composition. So, to answer your question the part of concern would be forged, most likely, stamped in a die, then subsequently solution heat treated and aged to the T6 or T61 condition. Hope this helps with your project.
I find it somewhat hard to believe these would be cast, when today you can water jet or laser cut a blank, clean it up, drill necessary holes, thread as necessary and ship the part.
Just my couple of cents worth of thought.
