Doors and hatches
Yellow Iron Hatch
Press & hold Activate to lock it or set a combination. Upgrade & repair with a construction tool using the secondary action.
Upgrade path
Hit a placed block with a stone axe, claw hammer or nail gun while carrying the material of the next step: 6 hits per upgrade.
Crafting
Craft at Backpack · makes 1
Crafted as Iron Hatch: pick this one of its variants when you place it.
Forged Iron× 10
Harvest drops
Iron× 20-30
Taken apart with a harvesting tool (axe, pickaxe, shovel), before perks and tool bonuses.
When it collapses
Falling, it leaves 
Scrap Metal Pile (75% of the time) where it lands.
Where to find (4 POIs)
Shotgun Messiah Factory (tier 5), Jeffelon Zuckergates Estate (tier 4), NDC Checkpoint Two (tier 3), County Line Substation.
Points of interest built with this block (any of its variants), the highest tiers first, from the game's prefab files.