CN2646516Y

CN2646516Y - Improved plastic coating steel tube

Info

Publication number: CN2646516Y
Application number: CN 200320110428
Authority: CN
Inventors: 蒋龙福; 谭希平
Original assignee: Yixing Zhous Pump Industry Co Ltd
Current assignee: Yixing Zhous Pump Industry Co Ltd
Priority date: 2003-10-25
Filing date: 2003-10-25
Publication date: 2004-10-06
Anticipated expiration: 2013-10-25

Abstract

The utility model is an improvement of PVC coated steel pipe which is characterized in that: the inner surface of the steel pipe is provided with screw shaped grooves. Thus, when coating, the hot melt coating layer can be partly inserted into the grooves of the inner surface of the steel pipe so as to increase the connecting fastness and the friction resistance of the inner surface of the steel pipe and the coating layer, prevent the plastic from expansion and contraction. The utility model eliminates the possibility of break the liner layer due to concentrated stress, greatly improves the connecting fastness of the coating layer and the surface of steel pipe and the PVC coat will not fall.

Description

The plastic-coated steel of improvement

Technical field

Model utility is about the improvement to plastic-coated steel, relates in particular to a kind of plastic-coated steel of alternating hot and cold coating difficult drop-off.

Background technique

Plastic-coated steel be by at the steel pipe inwall with plastic spraying hot melt one deck plastic layer, as PE or PO.Though during plastic-coated steel pipe internal-surface is handled, as shot blast, the steel tube surface rusty scale is removed and crudeization of plastic and painted surface, with the fastness that combines of increase coating layer with steel pipe internal-surface.Yet because the thermal expansion coefficient of metal steel pipe and plastics lining is inequality, both differ nearly about 10 times usually, and as under 100 ℃ of temperature difference, the steel pipe prolonged expansion is about 7/1000ths, and the specific elongation of plastic coating is 6/1000ths.Therefore plastic-coated steel uses the big and alternating hot and cold occasion in the temperature difference, and plastic coating can produce stretchability and peel off, and can concentrate because of flexible stress when serious, make coating especially lining coating drawing crack separation come off, lose the coating protection effect.And this specific elongation difference raises along with temperature and strengthens, and especially when caliber was big, the relative cumulative bad amount of deformation of big lining area was big, and coating more is easy to generate contractions, cracking, separation and comes off.Caliber, therefore can be welded to connect steel wire, protruding nail etc. at inner surface of tube and prevent the measure of peeling off at inner surface of tube by measures such as welding because of the people can enter operation in the pipeline greater than the pipe of 600mm.And be the steel pipe of 150-500mm at caliber commonly used, because caliber is less relatively, the people can't enter construction in the pipe, steel pipe is still the light face with coating layer and combines as Fig. 1.

Summary of the invention

The purpose of model utility is to overcome the deficiency of above-mentioned prior art, and it is strong to provide a kind of plastic coating and steel pipe to combine fastness, the not easily separated plastic-coated steel that peels off.

The model utility purpose realizes, the main improvement is by processing spiral groove at steel pipe internal-surface, thereby make approximate smooth combination of coating layer and steel tube surface, become part and inlay combination, with this improve both in conjunction with fastness, make plastic lining when dilatation, stress looses in groove coupling punishment and eliminates, and prevents effectively that internal lining pipe stress from concentrating and the cracking that comes off that causes.Specifically, the model utility plastic-coated steel comprises the coating layer of steel pipe and internal surface it is characterized in that said steel pipe internal-surface has spiral groove.

The described spiral groove of model utility is not to be necessary for the standard thread structure, and it can be a kind of irregular spiral chute.Groove depth is comparatively suitable with 0.2--2mm, and pitch of grooves is better with 5-100mm.

The model utility plastic-coated steel is because employing is processed with spiral groove at steel pipe internal-surface, thereby coating layer is partially submerged in the steel pipe groove in reflow process, effectively strengthened the friction resistance between steel pipe and the plastic layer, stoped the plastics distortion of expanding with heat and contract with cold flexible, eliminate stress and concentrated the possibility that causes the inside liner drawing crack, thereby improved the be connected fastness of coating layer with steel tube surface greatly, plastic-coated is not easily separated to come off.

Below in conjunction with an embodiment, further specify model utility.

Description of drawings

Fig. 1 is existing plastic-coated steel cross-sectional view.

Fig. 2 is a model utility embodiment cross-sectional view.

Embodiment

Embodiment: referring to Fig. 2, it is that 1mm, pitch of grooves are the spiral groove 3 of 30mm that the preceding internal surface at steel pipe 1 of plastic-coated is processed with groove depth, and during the liner plastic-coated, hot melting plastic layer 2 partly is embedded in the groove with the steel pipe junction plane.

Claims

1, a kind of plastic-coated steel comprises the coating layer of steel pipe and internal surface it is characterized in that said steel pipe internal-surface has spiral groove.

2,, it is characterized in that said groove depth is 0.2--2mm according to the described plastic-coated steel of claim 1.

3,, it is characterized in that said pitch of grooves is 5-100mm according to claim 1 or 2 described plastic-coated steels.