The traddtional surface treatment without anything,after hot treatment,and then take them to install the sofa frame.Up to now,the North Americal,such as America,Canada still keep the same springs.
Nowadays,the people have more requirements,they hope the springs can be keep longer and don't be antirust.so ,the surface treatment of upholstery zig zag springs have 6 types now.Paniting,Antirust,Eletrophresis,Plating Zinc,Chrome.
It is very popular 6 years ago,but the now they don't like it,bcs it is not good smell and not inviromental .
2.Antirust,Same as the color of wire
It can be accepted by all the people,without chemical odor,and color is same with wire,anti-rust capability is quite good,price is cheaper.
Surface is smoothy and anti-rust capability is good,but the price is higher.
Color is silver,the anti-rust is very good,but the price is very higher,most of people can't accept it.Normally ,higher USD300 than the mormal springs.
Have varity of colors,anti-rust capability is the best,but the price is the highest,uaually,the factory used them in the outdoor furniture.
Pls contact me if you want to know more springs' knowledge.