316mod is modified 316, an improved 316L, which is specially used in the chemical fertilizer urea industry, so it is also called urea grade 316L.（Pall ring 316Lmod Urea）By adjusting the additive components, the ferrite content in the steel is suppressed to improve the intergranular corrosion resistance and selective corrosion resistance of the steel. Both urea grade stainless steels are subject to Hugh’s test and selective corrosion test.

（Pall ring 316Lmod Urea）It was invented by German BASF, the first generation Plastic Random packing. To compared with Raschig ring,the most important improvement is increase two row of inward ligule. It （Pall ring 316Lmod Urea）promotes liquid-gas liquidity and improve tower’s packign’s mass transfer performance.