As a professional Hot Elbow Machine Supplier, today we would like to share with you how to design hot elbow mandrel. I hope you can learn about the methods through this article.

1.Hot Elbow Forming Technology

The concept of hot elbow forming technology is based on the metal material plasticity deformation remains the same to design, that is ,mother pipe volume is equal to elbow volume.

No.1 Elbow

No.2Induction Heating Coil

No.3 Heat Preservation Device

No.4Mandrel

No.5Pusher

No.6 and 8 Clamp Part for mandrel rod

No.7 Mandrel Rod

No.8 Mother Pipe

No.9 Loading Part

No.10 Driven Part

No.11 Foundation

①Loading Step: We can take the steel mother pipe go through the mandrel rod , one rod can hold fully ,exactly number depends on the length of mother pipe , normally one hot elbow machine will make a short range of elbow .Then driven part will push them to the front mandrel without induction heating .

②Induction Heating Step :When arrive at the setting temperature , then hot forming with the pusher pushing .Mainly two big metal deformation one is diameter bigger and the other one is bending .

③Forming Step : When the elbow left the mandrel , then one elbow is finished .

When forming process , the pushing force will force the mother keeps Radial compensation, so the wall thickness is almost no difference with the mother pipe .And intrados and extrados are almost the same .

2.How to define the dimension of hot elbow mandrel dimension

2.1Mother Pipe model confirm

Let us take one example .Elbow Size :φ558.8mm×22.2mm Bending radius 838mm . and the wall thickness/OD is 22.2/558.8=0.03mm. It belongs to the thin elbow range .So the formula is as follows;

Do: Mother Pipe OD mm

D:Elbow OD mm 558.8mm

R:Bending Radius,mm 838mm

Do=418mm

Since φ418mm is close to φ406.4mm，and almost no wall thickness changing so we can choose φ406.4mm ×22.2mm.

2.2Define the dimension of mandrel

Mandrel is including three phases one is filtration process ,deformation process ,sizing process.

2.21: Filtration Process:the function is to position the mother pipe .

d1 = mother pipe OD -(2×mother pipe wall thickness + x)

X: the gap between the mother pipe ID and the mandrel , X=6mm)

So d1=406.4-(2×22.2+6)=356mm

Filtration length L=2d1=2×356=712mm

2.22：deformation Process

This phase mother is happening OD changing and bending ID changed to Elbow ID , mother pipe OD changed to elbow OD .bending radius changed to elbow radius .,then we calculate the mandrel dimension .We can define the 45 degree .

d2=elbow OD -2×Elbow wall thickness

=558.8-2×22.2=514.4mm

Considering the thermal expansion to d2=516mm

H: from the 90 degree elbow end to Filtration center height

H=R+d2/2-d1/2

=838+516/2-356/2=918mm

Deformation Extrados bending radius:

R1=R+d2/2=838+516/2=1096mm

Deformation Intrados bending radius:

R2=(R-d2/2)+2(d2-d1)/Sin45degree =1033mm

Sizing Process :

This process is to make the elbow OD and bending better .

Sizing extrados bending radius: R3=R1=R+d2/2=1096mm

Intrados bending radius: R4=R-d2/2=580mm

End

If you want to learn more about hot elbow forming , please feel free to contact me .

Contact: Mr.Dong 

Email: lmdzjxc@lmdzzjxc.com

Web: www.limingbending.com 

Mobile:0086 13931703233