NTK D series control the content of the nickel, which improves the content of manganese, and D series is an austenitic stainless steel which consists of Cr-Mn-Ni-Cu also adds copper.
NTK D-11 is austenitic Stainless Steel which modifinged by adding Cu in AISI 201(EN1.4372). It shows mechanical property and corrosion resistance which are near for Type 304. And magnetic permeability of this alloy, when cold worked, is lower than that of Type 304.

NTK D-21 is an austenitic stainless steel containing Cu, and accommodates to SUS304J2 of the Japanese Industrial Standards(JIS).
This alloy is softer than Type 304 and shows equal cold work hardenability to SUS XM7.
And magnetic permeability of this alloy, when cold worked, is similar to that of SUS XM7.

NTK 301HD is the austenitic Stainless Steel, having more excellent work hardenability than type 301, while its chemical composition is within type 301.
This alloy has high strength and high hardness by cold working, so it is usually used in cold worked condition.
This alloy has higher elongation than type 301 on the same strength level , so its formability is improved from type 301.
NTK D-7S is an austenitic Stainless Steel containing lower Nickel contents, higher Manganese contents and also containing Cu. It shows the higher strength than Type 304, and it also shows both near corrosion resistance and near cold work characteristics by Type 304, and can be used in cold worked condition.
NTK S-4 is hard and non-magnetic stainless steel which has a high cold work hardenability and a low magnetic permeability.

NTK U-20 is 28%Cr-3.5%Mo high-purity, high-corrosion resistant ferritic stainless steel with ultra low carbon and nitrogen. NTK U-20 has highly excellent resistance to stress corrosion cracking in chloride environment, and also has excellent resistance to pitting corrosion and crevice corrosion. NTK U-20 contains small amount of niobium to prevent intergranular corrosion of welds.
NTK U-22 is 22%Cr-2%Mo high-purity ferritic stainless steel with ultra low carbon and nitrogen. NTK U-22 has excellent resistance to rusting corrosion, so it is suitable for architecture exterior in seashore environment. NTK U-22 is almost immune from stress corrosion cracking in chloride environment, and it has excellent resistance to pitting corrosion and crevice corrosion. NTK U-22 contains small amount of niobium to prevent intergranular corrosion.
NTK U-24 is 22%Cr-1%Mo ferritic stainless steel with ultra low carbon and nitrogen, having highly excellent resistance to stress corrosion cracking in chloride environment. NTK U-24 has equally excellent corrosion resistance to Type 444, that is, it has excellent resistance to pitting corrosion and crevice corrosion. NTK U-24 contains small amount of niobium to prevent intergranular corrosion of welds.

"Swan-color F shanetsu" refrects all most of infrared rays , so temperature of under"Swan color F shanetsu"　roof is lower than"Swan color F" roof.
"Swan-color TITAN" has the photocatalyst function.