Hardness of Quench and Tempered alloy steels is a function of the tempering temperature. The higher the tempering temperature, the lower the hardness.
This is called an inverse relationship.
And it’s why some people call tempering “drawing.”
The temper “draws the hardness out of the steel.”
These curves are a rough approximation of the as tempered brinell hardness for the grades shown. For example, I have other data for 4340 that shows 440 BHN at 800F; 410 at 900F; 380 at 1000F; 340 at 1100F, and 310 at 1200F temper temperature.
Your mileage may vary, in other words, but this graph is close enough for ‘considered judgement.’
Additional 4140 data that I have from my notes suggests 397 BHN at 800F; 367 at 900F; 335 at 1000F; 305 at 1100F and 256 at 1200F.
If you have better data from your process – USE IT.
Better yet, if you have time, send a sample to your heat treater for a pilot study.
In the absence of data from your process, the above figure and data will give you “a place to stand” in understanding what is possible when heat treating .40 carbon alloy steels- the steels most commonly encountered in our precision machining shops for Automotive, Aerospace, Agricultural and general applications.
Here is a video from PMPA member company Nevada Heat Treating to give you an inside look at what goes on at a heat treat service provider.
Author: speakingofprecision
To advance member companies is part of the PMPA’s Mission; “to identify legislative issues having a significant impact on the Precision Machining Industry… to provide information to impact those issues” is part of the PMPA Government Affairs Committee’s Mission.
The Small Business Jobs and Credit Act of 2010 signed into law today by President Obama, includes the following provisions to help small manufacturers remain competitive: It creates a $30 billion lending fund to provide community banks with capital to increase small business lending
- Expands access to and lowers the costs for small business to access Small Business Administration (SBA) loans and increases loan limits
- Spurs investors by giving 100% exclusion from capital gains taxes on small business investments
- Reduces small business taxes by allowing them to carry back general business tax credits to offset their taxes from the previous five years
- Doubles small business expensing for immediate write-offs of capital investments, such as equipment and machinery, in 2010 and 2011.
- Extends bonus depreciation
- Spurs investment and growth – giving small businesses more cash on hand to create jobs
Government affairs work takes time. Passion. Patience.
News Release
We’re glad to show that the hard work of our Government affairs committee has had a desired result: Legislation releasing money for small business loans to help us stay competitive, hire new employees, and restore American Manufacturing’s Competitiveness.
Thats just one thing that our trade association has done lately.
EMC Precision
PMPA Membership
Just like you, we are getting important work done. Shouldn’t you belong?
Any questions?
Our comment for this is three words recalled from Mrs. Ponte’s Latin Class: ‘res ipsa loquitor.’
Translation: ‘The thing itself speaks.’
Data: Federal Reserve Bank of St. Louis; Manufacturing Employees (MANEMP)/ Total NonFarm Payrolls; All Employees (PAYNSA)
Original source FRED
We found it Here. (Paul Kedrosky Blog)
Sometimes the wisdom is just undeniable.
I spend quite a bit of my time writing what I hope to be interesting articles for our many readers. Knowledge retention and thought leadership posts for our member companies.
Written pieces that give the readers ‘Tools They Can Use.‘
If I’m writing, I’m probably not spending a lot of time reading…
So when I got a copy of ph Horn’s latest World of Tools 2/10 magazine, I was captivated by the following comment made by Lothar Horn, Managing Director.
“How can our tools best be used so that the customer can obtain the maximum benefit from this investment?”
At PMPA, we’re pretty familiar with the concept of ‘Tools You Can Use’– in fact we use it as our Tagline.
But we were really interested in the answer that Mr. Horn gave to his own question:
“…we have developed new products, strengthened support and service and expanded our portfolio in the direction of complete machining.”
Let’s see, how can we as an industry face the challenges of the current market situation?
1) Use the tools we have to develop new products,
2) Strengthen support and service to our customers,
3) Expand capabilities toward complete solutions…
Couldn’t have said it better myself!
You can download the Horn World of Tools Magazine at this link ; just click on the pdf download link for the 2/10 issue.
If this was a quiz, would you have gotten 3 out of 3?
OK, I ‘ll admit I’m really a sucker for cool science demonstrations.
Just like the current administration is a sucker on currency manipulation by the Chinese.
Sorry about that.
So while you and I probably can’t afford to rent the high energy equipment the folks at Popular Science used for their video, you can get instructions that describe how you to can capture Lichtenberg patterns of static electricity. This Pop Sci Site tells you how to make cool lightning (static electricity) images using some plastic sheet, a nail, and your favorite source of static electricity :
I think it will be a great project for this winter when everything that I touch yields a spark to my touch.
Cat photo from static electricity blog here .
Send me your photos of your static electricity demonstrations and I’ll post them here.
Warning: Do not use the hammer and nail on the Cat!
Three points you should know about the EPA’s proposed TRI ‘Clarification’
- It underestimates industry burden. It would cost our Precision Machining Industry on the order of $3,534,104 in preparation, collection of data, analysis and reporting costs.
- This impact falls mainly on our small businesses – 54 % of US Precision Machining shops employ less than 20 employees.
- The “Clarification” does not provide a positive impact on public health and safety, and it wil llikely foster over reporting, double counting of “releases” and otherwise mislead the public.
We recently attended a meeting with the Office of Management and Budget (OMB) and Environmental Protection Agency (EPA) officials regarding EPA’s proposed “Clarification” of the Article exemption under TRI 313 Reporting. We were joined with representatives of roughly 14 other industry spokespeople at this meeting.
Read our submission to OMB and EPA.
Many precision machining shops make use of the article exemption in some form, so any changes to the definition would require all precision manufacturing companies to reassess their need to report under the new clarification. In the US, that means 3,364 perecision machining establishments would need to spend, according to the EPA’s own estimates, 51.3 manhours to properly evaluate and report.
While the EPA’s federal register comments indicate that only the treated lumber industry would be affected, representatives from a wide range of industries were in attendance to show how the proposal would eliminate the Article Exemption for their products.
PMPA was there to show how, if the Article Exemption were lost, the reporting burden for our industry would be orders of magnitude higher than the EPA’s estimate of $13,877.
$13,877!
That’s right. EPA thought that the TOTAL INDUSTRY Reporting Burden for this “Clarification’ would be no more than $13,877.
Using the 2007 Survey of Manufactures data from the U.S.Census, We were able to show that the cost of evaluating our new reporting status as an industry would be at least $3,534,104. That is just for Precision Machining Shops.
For Fabricated Metals, which includes Precision Machining, the burden jumps to $66,235, 899. And for the entire 33 NAICS code, including Precision Machining, Fabricated Metals, and Machinery Manufacture, the impact is over $209 Million Dollars.
EPA’s estimate of Reporting burden for NAICS 33XXXX underestimates by a multiple factor of 15108.83 times.
PMPA’s mission and vision charges us to provide resources that “advance and sustain” member companies within the Precision Machining Industry.
That’s why we went to Washington. To save you and 3,363 of your peers from a “clarification” that would have burdened the industry to the the tune of about $3,534,104. Or US manufacturers in NAICS 33 about $209 million.
EPA would better serve its mission by clearly defining what is a release, and exempting legitimately recycled materials such as scrap metals from TRI reporting.
That’s is a change we could support.
Read our submission to OMB and EPA.
In steels, tempering is reheating hardened steel to some temperature below the lower critical temperature for the purpose of decreasing hardness and increasing toughness.
(The lower critical temperature is the temperature of the austenite-to-pearlite eutectoid transformation in steels- below this temperature austenite does not exist.)
Tempering is also sometimes applied to normalized steels. For the same reasons- decrease hardness and improve toughness.
The chart above shows the colors that are elicited by tempering a 0.95% carbon content steel at the temperatures shown. (Think drill rod.)
I saved this chart back in my youth from a Bethlehem Steel Handbook.
This is what we here at PMPA call “Knowledge Retention” and “Tools You Can Use.”
After postponements and a head fake by the Chinese, the US Department of the Treasury has once again failed to name China as a currency manipulator.
You can read the Treasury Department Report to Congress here.
Here’s what Treasury Tim Geithner had to say:
“What matters is how far and how fast the renminbi appreciates…We will closely and regularly monitor the appreciation of the renminbi and will continue to work towards expanded U.S. export opportunities in China that support employment in the United States, in close consultation with Congress.”
Hey Tim, how many more years do you guys think you’ll need to closely and regularly monitor this?
| Chinese Yuans to 1 USD (invert,data) | ||||||||||||
Chart courtesy xrates.com |
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When do you guys think it will be time for action? This is the same old do nothing approach we suffered through from the last administration. (PMPA has been active on this issue since 2004 when we joined the China Currency Coalition)
When was that “Change”you guys campaigned about supposed to arrive?
On the China Currency Issue, NOTHING HAS CHANGED.
We mentioned this before here, here and here.
So what can you do? Help us get Congress to do what the Administration can’t won’t.
National Currency Call-in DayInstructions. Today!
Manufacturers from all across the United States will be contacting their legislators asking them to support Senate Bill 3134 and co-sponsor House Bill 2378.
Congress needs to hear from manufacturers on this important issue, so they’ll move on legislation to provide the Administration with additional tools to prosecute illegal currency manipulators. Clearly, the Executive Branch can’t get it done.
The time to act is now.
Photo credit: Poster, Yuan
Chromium is added to steel to
- Increase resistance to corrosion;
- Increase resistance to oxidation;
- Increase hardenability;
- Improve high temperature strength;
- Improve abrasion resistance in higher carbon grades.
Chromium forms complex chromium-iron carbides. These carbides go into solution into austenite very slowly, so assuring a long enough heating (soak) time before quenching is very important.
In stainless steels, ~18 % chromium is typical, (303, 304 austenitics), while analyses as low as ~12 % (403, 420), and as high as 26-28% grades are available.
In non-stainless steels, chromium is essentially a hardening element. It is often used in combination with nickel (a toughening element) to produce improved mechanical properties. In combination with molybdenum, chromium contributes to higher strength at elevated temperatures.
Chromium’s principal use is in stainless steels, where its resistance to oxidation provides the protection from oxidation and corrosion.
Chromium’s decorative properties made it a favorite among automotive and motorcycle enthusiasts. Its resistance to oxidation and staining and ability to take a high polish make it an easy choice for decorative yet functional parts. Chromium’s hardness and chemical resistance makes it ideal for protecting our tools.
Chromium has several oxidation states, Hexavalent chromium (CRVI) is of concern as an industrial environmental issue. Metallic chromium is not hexavalent, but flame cutting or welding of chromium materials may release haxavalent chromium. Chromic acid used for some chrome plating applications is hexavalent. Newer environmentally acceptable chromium finishes are trivalent. (CRIII) Link.
Chromium is named for the Greek word chroma, meaning color, as its salts are brightly colored. Chromium is a constituent of rubies, and is why ruby lasers give off their characteristic red light.
Final chromium fact: your body requires chromium. Chromium in your body ranges from 6-100 ppb in blood, up to 800 ppb in various tissues. Depending on your mass, you might contain as much as 12 milligrams of chromium in your body.
Reference.
We all know that customers want ever decreasing prices.
GM and Chrylser bankruptcy and bailout showed us how that thinking turns out.
So what do customers really want? Here are my top three ideas:
Solutions.
Customers want solutions. They don’t want to buy your product. They want to solve their problems.They want to see their problems go away. Are you selling products when they are looking for solutions? How is that working out?
Service.
Customers want service. They want it now. Lead time is so, so , 20th Century. It is a global, inter-networked- 24-7 world today. Some body has what they need. The first one to say yes gets the order.
Value.
Customers want value. Not cost. Value. Customers will pay for what they value. Not just pay for what it cost you, but for what they value. Is it really a “deal” if you have to take the “gi-normous” soda when all you really want is the sandwich? How much “soda” are you pushing to your customers when all they want is the sandwich?
Solutions. Help them solve their problems with <gasp!> the products that you can deliver this week. Service. It is no surprise that all mature economies become more and more service oriented. People want to be served. Customers are people. Value. The customer tries to get you to lower your price. you think that it is about lowering cost. What the customer really wants is higher value.
Thats what I think.
Solutions. Not products.
Service. Not promised delivery. Delivery!
Value. Not a deal where they get crap stuff they don’t really need.
These are the three things that customers want.
What do your customers want?
What do you want?
I’ll bet its the same things.
