Just to add to what MagBen said, it is impossible to obtain round steel bars as Cold Rolled. Round steel bars can be Cold Drawn through a die, but not rolled. So specifying CRS will only lead to confusion. Cold drawing is very common in sizes below 2" in diameter. Very uncommon in sizes above this.
A356 with T6 heat treatment (solution treat + artificial aging) is the standard high strength alloy for sand and permanent mold casting. Here are some links with data on fatigue properties including S-N curves:
https://tel.archives-ouvertes.fr/file/index/docid/661622/filename/Angeloni2011.pdf...
AEKen,
For the solution heat treatment time, did you consult Table 3 of ASTM B918? The time depends on the thickness of the part. Regarding T73 precipitation treatment, this is a 2-stage process that must be performed in the correct order:
1st precipitation treatment is 215-235 F for 6 to 8...
olds,
Sorry for the delay in responding, regular work has been busy the past week. Anyway, if I understand you correctly, you are saying that this part has a cross-section that is a maximum of 1.3 mm? That is extremely small for a carburized part. Most carburized parts are shafts or gears with...
In my experience, the automotive industry routinely carburizes 20MnCr5 to achieve surface hardness > 58 HRC with less than 25% RA (usually much less than this) without using a sub-zero/freezing step. Surface carbon is usually in the range of 0.7 to 0.9%. One critical factor is the geometry of...
petar,
Automotive shafts for driveline and transmission applications are either surface hardened by induction heat treatment, or by case carburizing. Typical surface hardness is 59 HRC minimum, which means that a surface bending stress under maximum load should be less than ~ 2200 MPa. The...
If this is made in Europe or Asia, it is quite likely that this is a standard grade of steel with a small Cr addition for increased hardenability, as metengr noted. 27MnCrB5-2 according to EN 10083-3 fits your stated composition if you include B in the range of 0.0008 to 0.005.
480 C (900 F) is the maximum recommended forging temperature for 6061 (ASM HANDBOOK Volume 4). It is possible that the high temperature is contributing to the blisters. Grain growth can occur at temperatures above 400 C, especially if there is any prior cold working of the surface, and this...
The addition of > 1.5% Ni increases the flow stress of the steel, making cold forging more difficult. The higher flow stress increases forces and hence stresses on the tools, which makes it more difficult to achieve adequate tool life. Most net-shape gears using EN353, SAE 4320, or similar...
Does the environment also have a component of exposure to ultraviolet radiation? If not, then I agree with suggestion of epoxy coating. If so, then you will need to evaluate some different coatings, because epoxies are degraded by UV.
I'm just getting back to reading this thread. High pressure die cast alloy 360 is NOT suitable for service near an ocean or other environment with continuous exposure to mist/spray/splash of saltwater. This alloy has very poor corrosion resistance. The pre-treatment for the coating will need to...
Can you provide some additional information:
- What type of welding process was used (GMAW, GTAW, LBW, etc.)?
- Was filler metal used? If so, which alloy?
- Corrosion in what environment?
In general, high pressure die castings do not have very good corrosion resistance, and welds will be even...
If the aluminum is not in contact with steel, stainless steel, or another metal that is galvanically more noble, then this alloy and coating combination should be ok for 5-6 years. A general urban environment is not very aggressive for even bare aluminum. Things like acid rain, animal waste...
