OST1 90201-75
OST1 90201-75 Grinded and mechanically calibrated bars of titanium alloys |
This industry standard applies to hot-rolled ground and mechanically calibrated bars of titanium alloys of grades VT3-1 and VT16, intended for the manufacture of fasteners by shrinking.
1. Product mix
1.1 Dimensions of round ground or mechanically calibrated bars and their limiting deviations shall meet the requirements of Table 1.
Table 1
| Dia, мм | Limit deviations in diameter, mm |
| 4,0 4,1 5,1 |
-0,030 |
| 6,1 8,2 |
-0,035 |
| 10,2 12,2 14,2 16,2 |
-0,100 |
Notes:
1. Bars of titanium alloy VT3-1 are produced with diameter from 8.2 to 16.2 mm.
2. Intermediate sizes of bars are produced by agreement of the parties.
1.2 Bars are supplied in lengths from 1 to 4 m. It is allowed to supply bars with length not shorter than 500 mm in the amount not exceeding 5% of the batch weight.
1.3 Curvature of bars per 1 pg. m of length should not exceed 2 mm.
The total curvature of the bar shall not exceed the product of the curvature per 1 pg.m by the length of the bar in meters.
1.4 Ovality and faceting of bars shall not take their dimensions beyond the diameter limit deviations.
2. technical requirements
2.1 Titanium bars are supplied in hot-rolled (drawn) condition after grinding or mechanical calibration without heat treatment.
It is allowed to supply bars after vacuum annealing with subsequent straightening and grinding.
2.2 The chemical composition of alloys should meet the requirements of OCT1 90013-71 (replaced by OST1 90013-81), and the aluminum content should be within the range of 2.2-3.8%, and the hydrogen content - no more than 0.012%.
2.3 Mechanical properties of bars shall meet the requirements of Table 2.
Table 2
| Ti Grades | Condition of the test specimens | Mechanical properties | ||
| Tensile strength, kgf/mm2, not less than | Relative, %, not less | |||
| elongation | narrowing | |||
| VT3-1 | Annealed | 100-125 | 12 | 35 |
| VT16 | Heat-hardened | 105-120 | 12 | 50 |
2.4 The surface cleanliness of bars shall be not less than 6. The surface of the bars shall be free from cracks, risks, roughness, stains, slicks, sunsets and sinks.
Local scuffs are allowed on the surface of the bars, as well as single local defects with a depth not exceeding the diameter limit deviation and not taking the diameter of the bar beyond the minimum dimensions.
2.5 The grain size of bars, determined on a 10-point scale of macrostructure, shall not exceed 3 points.
2.6 The microstructure of BT16 alloy bars, determined on a 9-type scale, shall correspond to 1-6 types.
Microstructure of bars made of BT3-1 mardo alloy shall meet the requirements of OCT1 90006-70 (replaced by OCT1 90006-86).
2.7 The macrostructure of the alloy shall be free of delaminations, cracks, voids, metallic and non-metallic inclusions visible to the naked eye.
