Talk:Work hardening

This article is written in American English, which has its own spelling conventions (color, defense, traveled) and some terms that are used in it may be different or absent from other varieties of English. According to the relevant style guide, this should not be changed without broad consensus.

Merge cold work into work hardening[edit]

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section.

I've started working on the merger in my sandbox. The link to edit the sandbox is at the top of my user page Xpanzion 07:12, 15 December 2006 (UTC)[reply]

The cold work and work hardening definitely talk about exactly the same thing and are complementary. They should be merged under a single article title with redirects in place. I prefer to merge under the title of work hardening because that is the most common descriptive name that I am used to reading and hearing for this topic. The term cold worked is usually only used as an adjective describing a piece of metal, but when talking about why cold rolled metal is stronger than hot rolled, people usually shift to talking about "work hardening" as the general process.--Yannick 03:34, 13 August 2006 (UTC)[reply]

Talk:strain hardening mentions an old plan to move cold work to strain hardening, but this was apparently never done. I never see or hear the term "strain hardening" except in material sciences textbooks.--Yannick 03:34, 13 August 2006 (UTC)[reply]

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

drilling and work hardening[edit]

Someone might want to add information about work hardening and drilling. When drills fail to penetrate some steel alloys, the heat buildup can toughen the material and make it harder to drill even more.

Not the same thing at all. Work Hardening is due to plastic deformation. What this note is describing is a purely thermal process and is not in any way shape or form cold work or work hardening. What usually happens is the drill bit itself loses it's heat treatment and the hard alloy steel wears away the sharpened edge of the drill bit. This rapidly becomes a feedback loop - the dull bit causes more frictional heating causing more dulling, and a broken bit follows in rapid order. —Preceding unsigned comment added by 66.117.135.63 (talk) 04:16, 15 March 2009 (UTC)[reply]

Actually, I think you are both right, depending on the case. Unintentional work hardening does sometimes occur in machining, with annoying results. — ¾-10 02:41, 22 January 2010 (UTC)[reply]

Removal of red links[edit]

I have considered to remove the redlinks without altering the content i will just remove the internal link format to make the page look a bit neat and informative. Any comments regarding this are welcome. Kalivd (talk) 15:21, 21 July 2008 (UTC)[reply]

I went through and linked some of the red links. The ones that are left I think can just be removed. Wizard191 (talk) 15:41, 21 July 2008 (UTC)[reply]

Proposed merge from cold forming[edit]

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.

The result was merge. Wizard191 (talk) 22:44, 17 October 2009 (UTC)[reply]

Cold forming is just an application of cold working. This article already references to cold working. Why make people look in two locations for one concept? --Wizard191 (talk) 01:39, 23 October 2008 (UTC)[reply]

I agree with this merger; the two topics are not identical but should be able to be covered well in a single article. We should consider, however, preserving the list of processes in the cold work article and perhaps even create a new list article from it. Jminthorne (talk) 06:46, 3 September 2009 (UTC)[reply]

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Lede too jargonistic?[edit]

I noticed that the lede here seems to be ripped from a third or fourth year chemistry book. Perhaps we would do better to simplify the terms in the lede, and then explain in more detail in the article itself. Throwaway85 (talk) 03:42, 17 October 2009 (UTC)[reply]

You are right, the intro should be more accessible. I'll see what I can do, but it's probably a long way off. Wizard191 (talk) 22:44, 17 October 2009 (UTC)[reply]

Confusing Yield-Stress Formula[edit]

In the "Quantification of work hardening" section, a formula for yield stress, T, is given, with a square-root dependency. Then right after the formula is introduced, it says, "The material exhibits high strength if there are either high levels of dislocations (greater than 10^14 per m^2) or no dislocations."

I believe it's the paragraph that's right and the formula is wrong, because it's incomplete. The formula needs boundary conditions, because clearly when the dislocation density is zero, the yield stress is very high (I presume because the atomic bonds are maximized in the crystal lattice), but the formula predicts a minimum for yield stress.

199.106.103.248 (talk) 04:40, 6 March 2010 (UTC)[reply]

Getting the word right.[edit]

The first sentence suggests that material that is work hardened is strengthened. Uhhh, isn't the reverse true? For example, doesn't work-hardening of mild steel actually make it more brittle and somewhat weaker? —Preceding unsigned comment added by 121.218.205.13 (talk) 09:34, 13 January 2011 (UTC)[reply]

"Hardening" in this sense is actually a misnomer, because work hardening processes don't actually harden the material, they increase its strength. The sentence is right, the terminology is just somewhat misleading. Wizard191 (talk) 22:11, 13 January 2011 (UTC)[reply]

Actually, in the case of mild steel, I think the first editor may be right. You can lower the yield strength of mild steel by applying a negligible plastic strain. This is, however, an exception to a more general rule. See this image for a visual. - Koenig (talk) 18:58, 2 August 2013 (UTC)[reply]

Imaginary Dislocations[edit]

I'm not confident the section on dislocations needed to be saying explicitly that they don't exist. They exist as much as a wave on the ocean or a warm front in the atmosphere do. While you could reinterpret the situation into one where they are all simply variations in some larger medium/object, it seems a bit...obtuse. And they definitely aren't as simple as vacancies. Darryl from Mars (talk) 06:25, 18 June 2012 (UTC)[reply]

New Work Hardening Stress-Strain Diagram[edit]

There is an obvious and easily understood way to illustrate strain hardening using a stress-strain curve. The diagram on p.9 of R. Hill's "The Mathematical Theory of Plasticity" does it perfectly, and it, or it's equivalent, should be integrated into this page: Hill's Diagram - Koenig (talk) 18:59, 2 August 2013 (UTC)[reply]

Work hardening at room temperature of Indium[edit]

As this relates to my PhD project, I've done some literature review on this. Reference [3] does NOT state that Indium doesn't work harden at room temperature - it only states that it doesn't work harden at cryogenic temperatures: "The indications are that the mechanism which causes work-hardening ceases to become operative at low temperature when moderate hydrostatic pressures are present." A different paper that I've found by R. Darveaux and I. Turlik (http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=113309) demonstrates work hardening in indium at room temperature, and in the conclusion states: "It was apparent that both work hardening and recovery processes occur in indium at room temperature..." -- Highwind ⁸₈⁸, the Fuko Master 01:20, 5 December 2013 (UTC)[reply]

Feel free to change the article and cite the refs accurately. The current version talks about "low temperatures" but doesn't make clear that cryo-level is apparently what they meant by low. Maybe you can rewrite those sentences to clarify. — ¾-10 02:13, 5 December 2013 (UTC)[reply]

It also sounds like indium work hardens at room temperature, but it also anneals at room temperature. If that is the case, the original statement is not too far off. Glrx (talk) 21:07, 7 December 2013 (UTC)[reply]

Undoing the merge of cold forming[edit]

Hi
In 2009, cold forming was merged into this article with no discussion. I am undoing the merge, as it is clearly not appropriate.
"Cold forming" is a set of processes, that are applied with the goal of producing certain metal objects. "Work hardening" is only a side effect of those processes; which may be desirable, or part of the goal, but is distinct from the process that causes it.
In the vast majority of cold forming applications, work hardening is inconsequential and ignored; in many other cases, it is a minor or major problem to be avoided, or undone by annealing.
There are many articles in Wikipedia that link or linked to "cold forming" or "cold working" assuming that it would be a description of the processes. Instead, since the merge readers have been redirected to a highly technical discussion of a possible side effect -- with a list of the processes, and their other consequences, buried at the end, almost as an afterthought. Undoing the merge fixes the old links and makes it possible for new material to link to the processes instead.
All the best, --Jorge Stolfi (talk) 20:17, 2 April 2019 (UTC)[reply]

I am new to this field, but I may have found a mistake in the figure[edit]

Here is the figure in question. The description contains: "... The strain can be decomposed into a recoverable elastic strain (ε_e) and an inelastic strain (ε_p). ...". My understanding suggests that ε_e and ε_p should swap places in the figure. Is this correct? Shelthome (talk) 08:32, 3 May 2024 (UTC)[reply]

I believe the diagram is correct. After reaching point 3, followed by the load being removed, the stress/strain declines at the rate E down to the horizontal axis to a point that, unfortunately, is not labelled. Let's call it point Z. Now we can say that, after the load is removed, the strain between the origin and point Z is permanent as the result of plastic action between point 2 and point 3. It is appropriate to label the strain between the origin and point Z as epsilon sub p.

The strain between point Z and point 3 is elastic because the stress/strain declines at the rate E down to point Z on the horizontal axis. It is appropriate to label all strain to the right of point Z as epsilon sub e. Dolphin (t) 12:19, 3 May 2024 (UTC)[reply]

Right! Okay, I see how that makes sense now. I was thinking that ε_p represented the travel from point 1 to 2, but in fact, it seems like we first perform "the experiment", and only then define point 2 using the final strain after the load is removed. Slightly backward from how I was first thinking about it. Thank you :) Shelthome (talk) 12:39, 3 May 2024 (UTC)[reply]