1. technical requirements

1.1 Tungsten rods must comply with the requirements of these specifications TU 11-77.
1.2 Chemical composition of the material depending on tungsten grades must comply with the following requirements.

Tungsten grade	Tungsten content (including thorium oxide), %, min	The sum of impurities and additives, %, no more	Thorium oxide content, %.
VA	99,95	0,05	-
BPH	99,90	0,10	-
ВТ-7	99,95	0,05	0,7-1,0
VT-10	99,95	0,05	1,0-1,5
VT-15	99,95	0,05	1,5-2,0
ВТ-30	99,94	0,06	2,5-3,5
ВТ-50	99,94	0,06	4,5-5,5

The sum of impurities according to TU 11-77 includes the following elements: iron, calcium, molybdenum, potassium, silicon, aluminum.
1.3 Delivery

Diameter	Length, mm, not less	Delivery condition
Nominal, mm	Variation %
1,0-1,9 in 0,1	±2,0	1000	drawn
2.0-2.4 in 0.2		600	drawn
2,6-4,8 in 0,2		600	forged
5,0-12,0 in 0,5		300	forged

Note:

• Upon agreement, delivery of drawn bars with diameter up to 3.0 mm is allowed.
• In each delivered batch 10% of bars with length not less than 70% of the ones specified in Table 2 are allowed.
• Bars of grade BA and BPH with diameter over 9,5 mm, grade BT-7, BT-30, BT-50 with diameter over 10,5 mm and grade BT-30 and BT-50 with diameter less than 2 mm are produced by agreement with the supplier.

1.4 The color of drawn rods shall be from black to dark gray. Color of off-white is allowed. Oxidation on the surface of forged bars is allowed.
1.5 The bars shall be without cavities, cracks, delaminations, large burrs and dashes. Small dashes, burrs, traces of forging or straightening within the diameter tolerance, as well as single large burrs on bars of brands BT-50 and BPH are allowed.
1.6. The ends shall be evenly trimmed. Minor chips are allowed.
1.7 Rods shall be straight. The slope of the deflection shall not exceed 1% of the measured length of the rod. As agreed with the customer, delivery of unstraightened drawn bars is allowed.