Welding Black Steel

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Working on my first real welding project after doing a fair amount of practice on scrap. Locally I was able to pick up these 36" drop sections but as you can see one is your traditional metallic silver while the other is blackened. I guess I"m not real familiar with this finish nor do I know if it will weld the same. I'm hoping to get a little education lesson/discussion on exactly what I'm looking at and possible challenges I might face before taking it to the gun. Thanks in advance.
Reply:resize the pic to 800x600 otherwise it chops off your text 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:Unfortunately I can't seem to get back into my original post to edit the picture. I guess in general I've got a piece of black steel and wanted to know a bit more about how the finish is created, can I MIG weld this the same as the piece to the right of it, any special prep work etc that needs to be taken into account. Thanks for the insight on picture size. I didn't realize it was so small.
Reply:Its the same steel as the silver one, but the silver one has been sanded to bright metal.To weld the black one, just hit the area to be welded with a grinder to get down to bright metal.
Reply:Just curious if this is what hot rolled looks like? Dark blueish literally black in color? Someone else I know mentioned that and said the one to the left is pickled in oil?
Reply:Sand the mill scale off prior to welding.www.tjsperformance.comDynasty 300 DXHTP 240HTP Microcut 380Hyperthem 85JD2 Hyd Bender and HF Hyd Ring Roller all in one =(Frankenbender)Bpt. Mill/DRO4' x 8' CNC Plasma TableInstagram: tjsperformanceYT: TJS Welding and Fabrication
Reply:Originally Posted by TJSSand the mill scale off prior to welding.
Reply:The dark stuff is mill scale.You should remove it before welding, although not always necessary.HRPO- Hot rolled pickled & oiled.pickled in acid, oiled so it doesnt immediately rust.Welding/Fab Pics: www.UtahWeld.com
Reply:Yes, the dark stuff is mill scale.  Formed from the hot rolled steel reacting with the air during the mill processing.Grind it off to clean, shiny steel before welding.  Mill scale is a form of iron oxide, which means it is not metal.  You weld metal, not 'non-metal'.disclaimer: some welding processes can 'tolerate' a certain amount of 'non-metal'  Flux processes (SMAW aka stick and FCAW) can usually tolerate the most amount of 'crud', then GMAW (aka MIG), and finally GTAW (aka TIG) which can generally tolerate the least amoutn of crud.But you ALWAYS get a better weld if you are welding clean. shiny metal.  Always.  The best laid schemes ... Gang oft agley ...