A36 Scale thickness

O

Oliver46

Aluminum

Joined

Apr 8, 2009

Location

Western Maine, USA

• Jan 9, 2022

• #1

Read thru a lot of threads on the topic, seems to get heated at times, however I just have a simple question(maybe). I've got a 4"rectangular square of HR A-36, from what I've read I should mill under the scale on the first pass if possible. So, for the question, just how thick should I expect the hard scale to be? I want to keep it as close to 4x4 as possible, while getting a very clean finish, and truly square corners!

 

O

Oliver46

Aluminum

Joined

Apr 8, 2009

Location

Western Maine, USA

• Jan 9, 2022

• #2

I did more looking in the internet, would anyone agree with the idea about .040" thickness?

 

D

Dave G.

Cast Iron

Joined

Mar 24, 2005

Location

Clev, OH

• Jan 9, 2022

• #3

My experience for bar stock is 1% weight loss, so 0.040" on a 4" plate would be in the same range.

 

M

MrWhoopee

Hot Rolled

Joined

Nov 8, 2017

• Jan 9, 2022

• #4

My guess is .020 - .040"

 

RC Mech

Stainless

Joined

Jul 21, 2014

Location

Ontario, Canada

• Jan 9, 2022

• #5

Sounds about right. I try to do a 0.050” face cut on larger hot rolled material like that to get under the scale.

 

gbent

Diamond

Joined

Mar 14, 2005

Location

Kansas

• Jan 9, 2022

• #6

You could pickle the scale to remove it.

 

Orange Vise

Titanium

Joined

Feb 10, 2012

Location

California

• Jan 9, 2022

• #7

Got pictures of the material?

Hot rolled square bar often has radiused corners. The bigger the bar, the bigger the radius. I wouldn't be surprised if 4x4 bar had 0.125" or larger corner radii.

The dimensional tolerances on A36 is also much looser than that of cold rolled bar like 1018.

Then on top of all that, there's the straightness (or lack thereof).

So with regards to milling 4x4 bar as close to nominal dimension with sharp corners, I think the scale thickness is going to be the least of your worries.

 

Turbowerks

Cast Iron

Joined

Nov 9, 2018

Location

Windom

• Jan 9, 2022

• #8

A36 is a pita! Not hard just messy not straight have to machine it just to locate it to machine it! Have a customer that buys a36 2 by 6 and needs finished parts 2.00 by 6 inch by 8 inches long + .005 - .000 showed him many times cant be done and be clean machined. Smh did i mention messy.


When I find it I don’t need it
When I need it I can’t find it!

 

S

scott-ak

Aluminum

Joined

Oct 12, 2021

• Jan 9, 2022

• #9

whenever possible I drop it in my tote of muriatic acid for a few and burn that stuff completely off before working it.

 

D

DDoug

Diamond

Joined

Oct 18, 2005

Location

NW Pa

• Jan 10, 2022

• #10

Yes to what Orange said.

I would go up to 4 1/2" to be certain.

Your retired ? you have time to whittle off a few extra passes to make certain
you get what you need.

 

Mtndew

Diamond

Joined

Jun 7, 2012

Location

Michigan

• Jan 10, 2022

• #11

Oliver46 said:

I've got a 4"rectangular square of HR A-36, from what I've read I should mill under the scale on the first pass if possible.

Click to expand...

Get HRA, you'll be better off and won't have to worry about hard areas.

 

B

BT Fabrication

Titanium

Joined

Nov 3, 2019

Location

Ontario Canada

• Jan 12, 2022

• #12

on average to clean up both sides, it also isnt ever flat, takes about 0.090 off both sides to get it clean. sometimes longer flat bar takes up to 0.120"

 

B

Brett W

Cast Iron

Joined

Jan 10, 2014

Location

Huntsville AL

• Jan 13, 2022

• #13

As mentioned above, if you have the option, toss it in the acid tank and eat most of it off. That is what I do if I can get the part in the tank.

 

R

RJT

Titanium

Joined

Aug 24, 2006

Location

greensboro,northcarolina

• Jan 13, 2022

• #14

I remember what a very well versed and intelligent steel salesman told me a long time ago about A36. He said, "The only thing I can guarantee about HRS is if you throw it in the ocean, it will sink". And I absolutely agree with him.