Make sure there is no silicon anywhere in your process especially in the machining coolant. Silicon will cause soft spots and does not burn off in the furnace, quite the opposite in fact.
If your parts are semi fininshed, a light zirconite blast will usually do the job of removing the...
Herc,
Check out the website http://www.themonty.com.
Gord Montgomery comes across all kinds of used equipment, and he may be able to find some of what you are looking for.
John
Denial ain't just a river in Egypt...Mark Twain
One thing that many people do not respect and may even be the cause for the differences in readings is the proximity of the hardness indentation to a neighbouring one. A good rule to remember is never take a hardness check closer than 3 times the diameter of an indentation. If you are too close...
One suggestion if I may, blasting with alumina grit is not going to help, on the contrary, blasting with a non-mettalic oxide can inhibit brazing even more. In fact alumina (aluminum oxide) is a common braze repellant/stop-off. Try using metallic blast like Nicroblast, or even silicon carbide is...
A quick and dirty way of quenching in a barrel or tub and get the quenchant warm without the need of a heat exchanger is to take a warm scrap metal part and heat it to 500°F and dump it into your cold agitating quenchant to raise its temperature. When the temperature is about right, quech your...
We (major aerospace engine manufacturer) often weld previously hardened material when necessary. It is critical to include a tempering (stress relieve) heat treatment afterwards.
That being said, even though it is normal practise to weld hardened parts as described above, we do not weld on the...
Hi,
Aluminum T0 is annealed, T4 is solution treated and naturally aged (at room temperature), and T6 is solution treated and precipitation heat treated in an oven, this is also called artificial aging.
Now to bring a T0 back to T6, you have to solution treat at 970°F +/- 10°F, hold for 35...
One thing though,..be sure not to finish machine your part before you do the second heat treatment,...you will have some distortion, and not knowing your tolerances it is something to keep in mind.
John
If desired, you can minimize oxidation/decarb on re-hardening by performing a copper plate all over to protect the parts. Something around 0.0005" thick should suffice.
John
Having had a lot of experience in welding,NDT and heat treatment,here is my two cents on the matter.
Generally speaking,performing an x-ray before and after PWHT is a huge waste of time. The sensitivity of x-rays are such that you will not necessarily see any cracks if they are too fine or even...
Hi,
Just to add, it is important that the shims be clean. Degrease them well and keep them wrapped in clean paper tissue and handle them onlt with clean white gloves to prevent contamination.
