2. Tutorial: Engineering technology Topic: Volume forging- drawing of wires and profiles Prepared by: Ing. Elena Nová Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

3. Volume forging- drawing of wires and profiles

4. Drawing tools are stationary drawing dies and gauges very abrasion stressed. Steel wire dies have about 2000kg of drawn material lifespan. If made from hardened steel lifespan is about 200 times bigger. Diamond dies are nearly indestructible. Wires to diameter of 1.5 mm are made from hardened steel (sintered carbides).

5.  Drawing die consists of more cones with different ‘top angles’. Their function is as follows:  Entry cone (introducing) is a cone with angle of opening 45 to 60 o, lubricating – the same angle, drawing – cone with angle 10 to12 o, calibration and exit cone.  Scheme of drawing die:

6.  Drawing dies are either ‘single’ or multiple.  As a lubricant is used an emulsion of phosphates, borax, soap powder etc. …  Diameter of hole equals to required profile.

7.  Wire drawing is divided into following technological procedures: 1. Simple drawing 2. Drawing with reverse motion (one direction drawing + reverse die draw (minimize drawing force and temperature), 3. Step drawing (deformation is distributed into more steps – requires higher drawing energy). Hot drawing – steels with lower forming ability, 4. Drawing at lower temperatures (achieving of higher strength)

8.  Machines used for drawing wires, profiles or rods are called – (drawing mills, non-reversible mills).  Plough rod mill:  Mill with linear stroke (carrier chain with jaws moves on a frame).  Drawing speed is between 30 to150 m.min -1 length about 60 m max.  Lubrication is provided during drawing by a ‘pressure greaser unit.

9.  Drawing Mill with linear movement.

10.  Other drawing mills:  2. Wire coiling mill:

11.  Wire coiling mills are:  1. single pass  2. multiple pass

12.  Accordingly to process  1. Slip less mill  2. Mill with slip  Mill has few wire coils on the drum preventing slipping.  Mill with slipping creates an excessive heat which must be removed.

13.  Scheme of slip less and slipping mill.

14.  What is called ‘a drawing tool’?  What material is used for production?  Describe cone function.  Lubrication used for drawing dies?  What is the name of units used for wire drawing and how are they divided?

15.  Translate:

16.  http://www.ksp.tul.cz/cz/kpt/obsah/vyuka/s kripta_tkp/sekce/04.htm