×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Zn and Sn in brasses and bronzes
3

Zn and Sn in brasses and bronzes

Zn and Sn in brasses and bronzes

(OP)
Dear all

I am in the middle of selecting either a brass or bronze for a pressure /wear situation  the pressure is around 350 Lb and the relative movement between the two is for a very short tine

I am wondering what the roles of Zn and Sn play when added   for example if I choose a bronze with 40% Zn does it have a better load carrying capability than bronze with only 20% Zn

What does Sn add to the mix ??
Kind regards in advance

Stephen

RE: Zn and Sn in brasses and bronzes

2
Typically, brass alloys are copper base that can contain  up to 40% weight percent zinc. Zinc, as an alloying element, strengthens the copper matrix (called alpha phase) and over 35% content will form a second solid solution called Beta phase (zinc rich) - a two phase structure. The appearance of the beta phase increases hardness and strength of brass. Small additions of tin are used to increase resistance to a corrosion problem with certain brass alloys called dezincification, and to increase strength. If the brass contains less than 15% Zn this corrosion problem will not happen. The copper-zinc matrix can be alloyed with manganese and tin to form manganese bronze alloys.

Bronze alloys contain copper and of course tin as the primary alloying element. The strengthening affect of bronze comes into play with other alloy additions like iron, manganese and aluminum or silicon to form aluminum bronzes.

Before getting into detail regarding the pros and cons of a bronze or brass alloy, what is your specific application?
Will there be lubrication?
Approximate service conditions (temperature/environment)?

RE: Zn and Sn in brasses and bronzes

(OP)
Hi there is for clutch plates in a friction disc  multi plate clutch, oil cooled the chain just dipps into the oil but the plates are not submersed

Spring pressure 350 psi total


kind regards for a great answer

stephen

RE: Zn and Sn in brasses and bronzes

Rylenfield;
Based on your description, I would probably use a phosphor bronze or manganese bronze alloy.

RE: Zn and Sn in brasses and bronzes

(OP)
That was on my list but I am worried about the heat and losss of  Uts , the heat in the current unit can get to around 300 deg c , as the plates show signs of blueing... due to slippage
So we had do tuck a few more plates in there to avoid slip ...

Thank you kindly for your help

Stephen

RE: Zn and Sn in brasses and bronzes

We have use Aluminum bronze in a low speed high torque brake application with good success.
Increasing the number of disks will not reduce slippage, only spread the heat over a greater area. To reduce slippage you must increase the pressure holding the disks together.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources