We have legacy part traditionally made from 9310 AQ steel, vacuum carburized and shotpeened. It is highly loaded in a semi-shock mode and under low cycle fatigue (75k cycle expected lifespan). Failure (cracking) of the component has always been a problem way before 75 k is reached. Changing...
I have a pawl looking type of part that is made from either 8620 or 9310 steel. It is carburized to an RC50 of .015" and then cryo treated and tempered back to a hardness of about 90 R15N. After heat treat certain critical sections are shotpeened .
The part is failing in fatigue. After about...
We are in need of a good hardness tester. It will need to do about 300 Rockwell C hits a day + the occasional R15N.
We are looking at the NewAge Indentron. Cost is about $17k.
Does anyone have any experience with this one or others?
TIA
I am in need of a good testing laboratory. The ones near us just do not have the experience or equipment necessary.
The lab should be able to perform complete failure analysis with in house
*SEM
*Grain Size determination
*Retained Austinite determination
*experience with failures of...
We are having a problem with wear on a 1/8' thk 4130 sheet metal lever. Currently the lever is Q&T to 50 HRC.
We are thinking about taking the existing levers and having them Ion Nitrided about 0.010" deep and then possibly PVD coating.
I am aware that the 50 HRC lever would decrease in...
We use some small 4370 investment castings that have been having problems with non-metallic inclusions. The foundry wants to raise the silicon content from 0.3% to 1.0% in an effort to help with the inclusions.
What would be the effect in raising the silicon content?
The castings are heat...
I have a question about road salt contamination of 5160 alloy bar. The bar in question was transported un-tarped and was contaminated with road salt.
During processing the bar is austenized, formed, quenched in oil then tempered to 46 HRC to make a spring.
Do you think the road salt could...
I have been thinking about the post on 1045 vs. 4340
http://www.eng-tips.com/viewthread.cfm?qid=190661&page=2
and have some questions about design methodology.
Lets just say one is designing a machine component and is considering a range of steels. Why is it totally necessary for the...
I am going to have some prototype parts laser cut from .125 " thk 4130 sheet. After cutting the parts will be heat treated to 48-50 HRC.
Is there anything I should be concerned with in reference to the heat affected zone from laser cutting after heat treat?
I am pretty sure it will not be an...
We had some failures in 4mm x 23mm pins that were either carburized or carbonitrided to about 60 HRC. Pins are 1215 steel. Failure was when pins were placed in bending which we did not think was going to happen in the application.
Pin have been redesigned with 4140 @35 HRC and are working...
We have a situation in our plant and I would like to ask advice on material choice.
We have a forming machine that wraps red hot steel bar around a 40mm diameter cylindrical mandrel to form a spring. About 15,000 springs are made off each mandrel per day. Due to the heat pick-up from the...
I have some small .150" dia pins 1" long that are in a critical area and are under bending fatigue, light impact and wear. Pins are machined with some small radiused grooves, heat treated then centerless ground. I am thinking of using 4340 at 50 HRC.
Is temper embrittlement something I should...
We have a .120" thk sheet metal pawl type part that has traditionally been stamped from 1050/1060 steel, milled to produce a sharp edge and then heat treated to 50 HRC.
Volumes are increasing and we want to look at a fineblanking.
The fineblanking people want to use 4130 as its easier for them...
Does anyone know what type of steel and heat treat are used to make forklift tines? Hardness? Are they forged or bent when hot out of bar?
Just courious for my own general knowledge.......I have never seen one break....
TIA
I am designing a type of muzzle break for small arms. One part of the brake will be directly impinged upon by the hot, erosive muzzle blast after the projectile has left the barrel.
I am looking for material suggestions. I am considering Inconel but was wondering if there might be some other...
I have an application for fineblanking a small part out of 9 gage (.149") carbon or alloy steel. The part is about .5x.7 inch with some precision holes and surfaces.
After the fineblanking process I want to heat treat the part to 55RC but I want to minimize distortion.
Any suggestions to my...
I am designing a machine and have a need to analyise how the mechanism inside is operating.
Specifically, there is a small spring loaded lever that is inside the machine. The lever is unlatched by another lever and the spring loaded lever moves under the power of the spring to strike another...
This might sound odd but I am trouble reaming a .1565" dia hole in 3/16" thick annealed 8620.
I just can't seem to get a good, on size consistent hole with a variety of reamers I have tried. I am looking for a hole that does not vary in diameter by more than +-0.00015"
Finally I found a...
If we acid pickle 8620 steel in the as cast condition and then machine and heat treat (carburize at 1700F) will the heat treating drive off any hydrogen or acid that is present in surface defects?
TIA
I would like to have some small investment castings Melonited (nitrocarburized). The foundry can make castings in any metal pretty easily. I am looking for a 55RC part that has decent impact strength and will take to the melonite process. The 55 RC should not degrade after processing (1075F)...
