Steel aerosol monobloc
A tin coated steel sheet is provided for manufacturing a drawn can having: a thickness inferior to 0.7 mm, a yield strength inferior to 400 MPa, an average grain aspect ratio below 1.5, a strain hardening coefficient below 1.5, a tin coating from 0.5 to 4.0 g·m −2 on a first face and from 2.8 to 11.2 g·m −2 on a second face, a chemical composition comprising in weight percent 0.002≤C≤0.09 and 0.0015≤B≤0.005 and a balance of Fe and unavoidable impurities, and the steel sheet having a ferritic microstructure with a mean grain size from 5 to 15 μm.
1 . A tin coated steel sheet for manufacturing a drawn can, the tin coated steel sheet comprising:
a steel sheet having a first face and a second face, the steel sheet having a thickness less than 0.7 mm, a yield strength less than 400 MPa, an average grain aspect ratio below 1.5, a strain hardening coefficient below 1.5, and a chemical composition in weight percent comprising: 0.002≤C≤0.09; 0.05≤Mn≤0.6; 0.0015≤B≤0.005; N≤0.05; Ni≤0.2; S≤0.03; P<0.02; Si≤0.03; Cr≤0.2; 0.01≤Al≤0.08; Cu≤0.2; Nb≤0.05; V≤0.02; Ti≤0.05, Fe and unavoidable impurities, the steel sheet having a ferritic microstructure with a mean grain size from 5 to 15 μm; and
a tin coating from 0.5 to 4.0 g·m−2 on the first face and from 2.8 to 11.2 g·m−2 on the second face.
2 . The tin coated steel sheet as recited in claim 1 , wherein the mean grain size is from 7 μm to 11 μm.
3 . The tin coated steel sheet as recited in claim 1 , wherein the tin coated steel sheet respects the following ratio: BMASS %/NMASS %>0.6, wherein BMASS % is the weight percent of boron and NMASS % is the weight percent of nitrogen of the steel sheet.
4 . The tin coated steel sheet as recited in claim 1 , wherein the tin content on the second face is from 4.0 to 11.2 g·m−2.
5 . A method for manufacturing the tin coated steel sheet as recited in claim 1 , the method comprising the following successive steps:
casting a steel to obtain a slab, said steel having the chemical composition;
reheating the slab at a temperature Treheat from 1100° C. to 1300° C.;
hot rolling the slab at a temperature from 1000° C. to 1300° C. to define a hot rolled steel sheet;
coiling the hot rolled steel sheet at a coiling temperature of at least 600° C.,
cold rolling the hot rolled steel sheet until a thickness below 0.7 mm is obtained to define a cold rolled steel sheet;
batch annealing the cold rolled sheet with a heating rate from 10 to 50° C. per hour, a soaking temperature from 600 to 700° C. and a soaking time of at least 1 hour to define an annealed sheet;
temper rolling the annealed sheet at an elongation rate from 0 to 15% to define a temper rolled sheet, and
tinning the temper rolled sheet.
6 . The method as recited in claim 5 , wherein the hot rolling is at a temperature from 1050° C. to 1150° C.
7 . The method as recited in claim 5 , wherein the coiling temperature is at least 625° C.
8 . The method as recited in claim 5 , wherein the cold rolling is at a rate from 80% to 90%.
9 . The method as recited in claim 5 , wherein the elongation rate is from 0 to 5%.
10 . The method as recited in claim 5 , wherein the elongation rate is from 3 to 15%.
11 . A one-piece aerosol can manufactured by drawing, redrawing, wall-ironing, varnishing, necking and curling the tin coated steel strip as recited in claim 1 , wherein the first face is located inside the aerosol can and the second face is located outside the aerosol can.
12 . The tin coated steel sheet as recited in claim 1 , wherein the chemical composition in weight percent consists of 0.002≤C≤0.09; 0.05≤Mn≤0.6; 0.0015≤B≤0.005; N≤0.05; Ni≤0.2; S≤0.03; P≤0.02; Si≤0.03; Cr≤0.2; 0.01≤Al≤0.08; Cu≤0.2; Nb≤0.05; V≤0.02; Ti≤0.05, Fe and unavoidable impurities.