Nickel-free copper-phosphorus weathering steel casting blank

The invention provides a nickel-free copper-phosphorus weathering resistant steel casting blank. The nickel-free copper-phosphorus weathering resistant steel casting blank comprises the following components: 0.05-0.10 wt% of C, 0.05-0.10 wt% of P, 0.05-0.10 wt% of S, and the balance of Fe; si: 0.30 to 0.50 wt%; mn: 0.40 to 0.55 wt%; 0.07 to 0.15 wt% of P; s: less than or equal to 0.005 wt%; cr: 0.3 to 0.5 wt%; cu: 0.2 to 0.5 wt%; 0.020 to 0.050 weight percent of Alt (aluminum nitride); ti: less than or equal to 0.035 wt%; ni alloy is not added; the balance is Fe and inevitable trace elements; the production method of the nickel-free copper-phosphorus weathering steel casting blank sequentially comprises the following process routes: molten iron desulfurization pretreatment, converter molten steel smelting, LF furnace molten steel refining and straight arc type slab casting machine continuous casting. According to the method, slag making material consumption and iron loss in the smelting process are reduced, t