-- The Home Page of the Finishing Industry

on this site
current topics
Live! From beautiful Pine Beach New Jersey: Welcome to the world's most popular metal finishing website

topic 43668

2024-T4 vs. 2024-T351 MATERIAL


Q. What is the difference between 2024-T4 and 2024-T351? Our customer has asked for a 2024-T4 (rod) but I am having trouble finding the T4 material.

Michael Markstrom
precision tool & die - Sioux Falls, South Dakota, United States

simultaneous 2007

A. I believe this may be what you are looking for:

T351- Solution Heat Treated and cold worked by stretching. Equivalent to --T4 condition. It applies only to 2024 plate and rolled bar and 2219 plate per MIL-A-8920

T4- Solution Heat Treated and naturally aged to substantially stable condition. Applies only to products which are not cold worked after solution heat treatment.

Callie J. Benson
- Eastford, Connecticut, USA


A. Both have been solutionized at 920 F, water quenched and then naturally age hardened at room temperature for 4+ days. The difference: after quenching, the T351 rod was stress relieved by stretching 1-3% prior to aging. Thus, T351 is more stable for machining, as T4 still has residual stresses from quenching: compressive near the surface and tension in the center.
T4 is perhaps better in some fatigue applications.

Ken Vlach
- Goleta, California
contributor of the year honored Ken for his countless carefully
researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work
which the finishing world continues to benefit from.


A. T351 and T4 are temper designations of the aluminium alloy. T351 is a solution treated, cold worked and naturally aged and substantially stable condition. It is stress relieved by cold stretching to a permanent set of 1.5% to 3%.
T4 is solution treated and naturally aged to a substantially stable condition. (Definitions from ANSI 35.1)

T351 can be heat treated to T4 by heating to 495±5C (time dependent on cross sectional thickness) and the either cold water or polymer quenched (again the delay time between heat treatment and quenching is dependent on thickness, but generally the quicker into the quench the better). The material should then be naturally aged at ambient temperature for a minimum of 96 hours before being released.

Alternatively you could consider buying it in the temper state you require, try ordering SAE-AMSQQA200/3 T4.

Brian Terry
Aerospace - Yeovil, Somerset, UK


A. Hi Michael,
T351 means "solution heat-treated, stress relieved through controlled stretching and naturally age hardened. The products are not straightened after stretching".
T4 means "solution heat-treated and naturally age hardened".
Now if your customer is asking for RODs in 2024 - T4 temper, then make sure that after extrusion the rods are solution heat-treated but no artificial age hardening treatment.

Good luck.

Srimay Basu
- Dubai, U.A.E.


Q. Hello
my name is Marius, I am a student at an engineering Faculty from Romania.
For my final project I need some information about one heat treatment for AA 2024.
I want to ask you if it is a heat treatment for aa 2024, and after this heat treatment to obtain a minimum yield stress value of 350 MPa

Maarius Marian
- Buzau, Romania

April 21, 2008

Q. Hi, I'm a drafter in the automotive industry. I came across some of our older drawings this morning that specify Aluminum 2024-T3511. No one here knows the difference between T351 and T3511. Can someone help specify the main difference between the two? Thanks!

Aaron Bizzell
Design drafting - Clover, South Carolina

January 31, 2011

A. The difference between t351 and t3511 is that t351 receives no further straightening after stretching and the t3511 receives minor straightening after stretching to comply with standard tolerances per machinist handbook.

Curt Cantrell
- Fayetteville, Tennessee, USA

May 3, 2012

Q. Hi.

Do you know of any books that will have all this information? I.e. a book which will specify the differences between T3, T351, T3511, T4, T42, T6, T6511, etc -- not only for 2024, but 7075, 6061, etc.

Thank you.

- Langley, BC, Canada

June 5, 2018

Q. Dear all, can you help me, where can I find thickness tolerance (geometrical data) for 2024 T4? Thank you.

Vasabi Suspent
- Munich, Germany

Alcoa Aluminum Handbook
"Aluminum: its forms, alloys, and tempers"

from Abe Books
from Abe Books

A. Hi Guillermo. The "T" series are 'thermally treated tempers'. The Aloca Aluminum Handbook explains it in the first few pages, then goes on to tabulate all sorts of data and properties for aluminum shapes. Good luck.

A. Hi Vasabi. The tolerances are going to depend on the shape, and they may or may not depend upon the alloy (depending on the shape). The Alcoa Aluminum Handbook has subchapters on tolerances for each of its sheets & plates, wrought products, extruded products, wire, etc.


Ted Mooney, Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey

If you have a question in mind which seems off topic, please Search the Site

ADD a Q, A, or Comment on THIS topic START an UNRELATED topicView CURRENT HOT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2019, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.