Steel Screw (box of 100)

Material Composition Assumptions

A standard box of 100 steel screws weighs approximately 100 grams total, with individual screws averaging 1 gram each. The composition consists primarily of carbon steel representing 98-99% of the total mass. A thin zinc coating applied through electroplating or hot-dip galvanizing comprises less than 1-2% by weight, providing corrosion resistance. Minor alloying elements including manganese, silicon, and phosphorus make up the remaining material fraction. The carbon steel contains typical concentrations of carbon ranging from 0.05% to 0.25% depending on the specific grade used for fastener applications.

Manufacturing Geography

China serves as the primary manufacturing region for steel screws, accounting for over 50% of global steel production capacity. The country’s steel industry relies heavily on the blast furnace-basic oxygen furnace production route, which dominates approximately 90% of Chinese steelmaking. China’s national electrical grid operates at an average carbon intensity of 555 gCO2e per kWh, reflecting the continued dependence on coal-fired power generation. This manufacturing concentration results from established supply chains, integrated steel mills, and proximity to iron ore processing facilities along China’s eastern industrial corridor.

Regional Variation

Manufacturing Region	Grid Intensity	Estimated CCI Score	Adjustment vs Default
China	555 gCO2e/kWh	2.8	Baseline
European Union	295 gCO2e/kWh	2.3	-18%
United States	386 gCO2e/kWh	2.5	-11%
India	708 gCO2e/kWh	3.1	+11%
Turkey	424 gCO2e/kWh	2.4	-14%

Provenance Override Guidance

1. Primary steel production method documentation specifying blast furnace-basic oxygen furnace versus electric arc furnace technology used by the steel supplier.

2. Scrap steel content percentage in the raw material feed, as recycled content significantly reduces the carbon intensity compared to virgin steel production.

3. Regional electricity grid data or renewable energy certificates for the specific steel mill and fastener manufacturing facility locations.

4. Transportation mode and distance documentation from steel mill to fastener manufacturing facility to final packaging location.

5. Zinc coating process specifications including electroplating energy consumption or hot-dip galvanizing fuel requirements for surface treatment operations.

Methodology Notes

• The CCI score represents cradle-to-gate emissions including raw material extraction, steel production, fastener forming, surface coating, and packaging into retail boxes.

• Scope 1 emissions dominate due to coke combustion and iron ore reduction chemistry in blast furnace steelmaking, while Scope 2 reflects electricity for rolling and forming operations.

• The functional unit covers one complete retail package containing 100 individual screws with standard zinc coating for corrosion protection.

• End-of-life recycling benefits are excluded from this cradle-to-gate assessment, though steel achieves 96% recovery rates in typical construction applications.

• Transportation beyond regional distribution centers and retail storage are not included in the current assessment boundary.

• Coating material production emissions are considered negligible due to the minimal zinc mass fraction relative to the steel substrate.