Which One is 8620?

[rwm]

John- Please elaborate on the spark test for my education. What would you expect to see with each of these alloys?

I did buy O1 from MMC that looked like that.

 

[j-becker]

In general, online metals is the specialist company here. While they were founded as ecommerce startup, they are now part of Thyssen-Krupp, a well known German steel conglomerate. Zoro on the other hand is just a retailer and aggregator of other companies catalogues. They usually have little idea about what they are selling. So without even looking at the pictures, my money would be on online metals.

 

[mksj]

They are probably both 8620, the one on the left is hot rolled, the one on the right is cold rolled and ground. Based on the tag 1R8620CD/1 assume it is 1" 8620 Cold Drawn 1 foot, the confusing factor is the yellow paint on the end of the rod that is usually seen with 01. 8620 is usually blue or blue/white but that is typically with hot rolled. I use quite a bit of O1 rod, I have not seen the cold rolled ground rod with a shiny finish, usually I see that more with the 4140 and 8620.

8620 Hot Rolled rod bar


8620 Cold Rolled rod and ground bar


O1 Cold Rolled and ground rod bar

 

[rwm]

One day I'm going to break into a warehouse with several cans of different color paint....

 

[Sailplane Driver]

I did a spark test. I tried some unknown (possibly 4140) very hard steel which had less sparks than either of the 8620. I also tried some O1 tool steel and it looked identical (at least to my uneducated eye) to the two 8620s. This is what I was looking for (from Wikipedia):



The 8620 and O1 were like A and/or B in the first graphic. It's hard to tell because they look about the same and I can change the quantity of sparks with pressure but I lean more toward A. The suspected 4140 was most like D in the first graphic.

 

[pontiac428]

Once you've narrowed it down to low-mid carbon low alloy steel, it's going to be really hard to speciate. The main thing you get with 8620 is a little added chromium. You're certainly not looking at manganese, tungsten, or silver steels, where the differences are obvious. X-ray spec or spark emission spectroscopy are next on the list. Of course, comparing the sparks of both sticks for similarity would be helpful.

 

[Sailplane Driver]

I'm going to contact Zoro tomorrow morning and have them check if the 8620 they have is shiny like what I received or if they accidentally sent O1.