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View Full Version : Any idea about 3-6kw PSU in the 48-60VDC range to power 2500-5000W ZVS induction heat



Boyan Silyavski
05-05-2020, 06:44 PM
Hi,
Will need something for heat treating knives, steel stamps and similar and was looking at aliexpress 2500w zvs induction heater boards. As i have pretty clear about the boards which are 2200 3000 4000 and 5000 w at 48VDC , when coupled with second hand PSUs from China, the shipping and eventual customs will be quite steep.

So the Chinese use some 3000w power supplies made for servers and sell them for 80e and for the 2500 board i need 1x and for the bigger boards i will need 2x

Problem, in Spain or ebay EU could not find similar for that money and i really would like to buy the 4kw heater board as its best price/money

In USA i found people use 6kw cisco PSU for server giving 54vdc, sells cheap there/ 20-50e/, but no luck here in EU.

Any ideas welcome how to power cheap that setup so i decide what board to buy? There must be something available here which people dont know that could do that and for cheap

Muzzer
05-05-2020, 07:36 PM
I bought some used Huawei rectifiers through Alibaba https://www.alibaba.com/trade/search?fsb=y&IndexArea=product_en&CatId=&SearchText=Huawei+Rectifier+R4850S

The supplier I used was Hong Telecom. However, you need a controller too if you go this route. IIRC, they are controlled via a CAN bus.

I can see quite a few rectifiers on UK ebay. Same comment goes if you use a modern rectifier - check if they need another module to make them work.
https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=48V+rectifier&_sacat=0&LH_TitleDesc=0&LH_PrefLoc=3&_osacat=0&_odkw=telecom+rectifier&rt=nc

Boyan Silyavski
05-05-2020, 11:48 PM
Thanks, i did not search them as "rectifier" . Checking them now and there are interesting ones

JAZZCNC
06-05-2020, 12:33 AM
Boyan if your wanting an heat treating oven then have a look at something like this. I've got the same setup regards PID temp controller and Kanthel wire setup for a smelting furnace for casting aluminium and they are relatively cheap, I think I paid about 20 for the PID controller and Temp Probe.


https://www.youtube.com/watch?v=hTOf59pa3sU

Boyan Silyavski
06-05-2020, 12:37 AM
Bought a cisco 6000w from Germany for 50e shipping included. now will see how to switch it on, only info i have found is how to connect 1kohm resistor on another model. But for the money decided to check it It will greatly cheapen the build

Boyan Silyavski
06-05-2020, 12:44 AM
Boyan if your wanting an heat treating oven then have a look at something like this. I've got the same setup regards PID temp controller and Kanthel wire setup for a smelting furnace for casting aluminium and they are relatively cheap, I think I paid about 20 for the PID controller and Temp Probe.


https://www.youtube.com/watch?v=hTOf59pa3sU

2 times i buy, repair and make as new. Comes a friend,pays me premium or begs me much and sell it to him. Last time one was even angry with me that i have sold it..

Dean, i have bought a 51CRV4 spring steel to make some throwing knives/ my new covid hobby if you believe it. And found some interesting document on internet that this particular steel instead of 120min in an oven like the above, it will take only 2 min at correct temperature if induction heated and then quench and for 1 min reheat instantly at 250 and temper.

So it will greatly shorten and simplify process, furthermore i need only tip and back hardened and tempered, so can do it one time each side.

Now i dont have to go to my friend shop and heat 10kw furnace for 1 knife

ngwagwa
06-05-2020, 03:14 PM
2 times i buy, repair and make as new. Comes a friend,pays me premium or begs me much and sell it to him. Last time one was even angry with me that i have sold it..

Dean, i have bought a 51CRV4 spring steel to make some throwing knives/ my new covid hobby if you believe it. And found some interesting document on internet that this particular steel instead of 120min in an oven like the above, it will take only 2 min at correct temperature if induction heated and then quench and for 1 min reheat instantly at 250 and temper.

So it will greatly shorten and simplify process, furthermore i need only tip and back hardened and tempered, so can do it one time each side.

Now i dont have to go to my friend shop and heat 10kw furnace for 1 knife

A friend of mine makes knves for a living and was looking into induction heating for his workshop but he gave up on the idea as if induction heating was used for hardening the material had to be long soak annealed and the cooling time was too long.

Boyan Silyavski
07-05-2020, 07:53 AM
A friend of mine makes knves for a living and was looking into induction heating for his workshop but he gave up on the idea as if induction heating was used for hardening the material had to be long soak annealed and the cooling time was too long.

Depends on the material. Some could have such a heat treating curve, that this method is impossible or impossible to control. But according to this study (https://www.researchgate.net/publication/325566168_Quenching_and_tempering_of_51CrV4_SAE-AISI_6150_steel_via_medium_and_low_frequency_induc tion), the exact steel i will be using even benefits much from using that method.

Normally the makers will use 15-40kw induction to forge meta, quick heat to temperatures for hammering it.

ngwagwa
07-05-2020, 08:08 AM
Depends on the material. Some could have such a heat treating curve, that this method is impossible or impossible to control. But according to this study (https://www.researchgate.net/publication/325566168_Quenching_and_tempering_of_51CrV4_SAE-AISI_6150_steel_via_medium_and_low_frequency_induc tion), the exact steel i will be using even benefits much from using that method.

Normally the makers will use 15-40kw induction to forge meta, quick heat to temperatures for hammering it.

The study you link to used conventional heating to normalize the material. They quote a time of 30 minutes at 870 C but don't mention the cooling down rate or time.

Boyan Silyavski
07-05-2020, 10:43 AM
The study you link to used conventional heating to normalize the material. They quote a time of 30 minutes at 870 C but don't mention the cooling down rate or time.

The material comes annealed and i will machine it, so no stress here. Its oil quenched, oil at 40C

ngwagwa
07-05-2020, 11:35 AM
The material comes annealed and i will machine it, so no stress here. Its oil quenched, oil at 40C

Go for it but there is a big difference between annealing and normalizing.

Boyan Silyavski
09-05-2020, 08:10 PM
A friend of mine makes knves for a living and was looking into induction heating for his workshop but he gave up on the idea as if induction heating was used for hardening the material had to be long soak annealed and the cooling time was too long.

The simplest way is a container full with ash, have done that and it works pretty well. Probably cools for a day or 2. Of course if the steel is more complicated temperatures must be pretty exact, modern powder steels and so, if i remember correctly.


Go for it but there is a big difference between annealing and normalizing.

Exactly, quick normalization if needed after the part is machined and grinded could be done , heat and leave at air.

If i work some material, i would study the documentation and recommended methods. There are also different types of annealing, if we look deeper, but as i said i have no reason for normalizing or annealing the material, when machined. I machine it with air cooling the bit so nothing heats and then belt grinder, same here.

In reality i wanted to make that from S7 steel as its the other steel perfect for the purpose due to the toughness, but can not find a sheet vendor in Spain. Probably some one sells it in Europe, but now with the covid... As its heat and leave to air harden.