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Info sheet: Heat source

Simufact.welding uses heat sources that have been

tested and approved for over 30 years. These heat

sources are mathematical descriptions of the

introduced energy distribution inside of the melt pool.The aim of the heat source concept is to model the

isothermal surface of the real melt pool and the heat

flow through this isothermal surface close to reality.

Effects of the melt pool flow are considered indirectly.

The geometric parameters of the heat source can be

taken from a micrograph.

Simufact.welding supports two predefined heat

sources:

1. Conventional: For gas welding manual arc welding!S" #S" and $% welding &normally distributed

double'ellipsoid volume source introduced by

"oldak ()*+,

2. Laser: For laser and electron beam welding

&normally distributed area heat source combined with

a constant cylindric heat source,

1. Conventional

2. Laser




The corresponding heat source parameters in the

tra-ectory dialog. They can be stored in a database for

later use.

The stored settings will be shown automatically in the

listing and can be used in other models.

(. efinition Conventional

The width &b, of the heat source model means half the

width of the real weld pool.

● The width &b, and the depth &d, can be identified from

a micrograph. /ll other values can be estimated by

the following rule:

Front length af : 0. 1 b2ear length ar : '4 1 b

● 5f a construction plan is the

basis for a first estimation thenthe geometrical parameters can

be estimated using the design

throat a:

epth d = a 6 '4 mm &including a penetration

depth for an acceptable root,

#idth b = a 6 (' mm

Front length af = &a 6 (4 mm,10.

2ear length ar = .1&a 6 (4 mm,




. efinition Laser

●

● For a laser heat source the energy input is divided

into a surface and a volumetric heat source. The

energy fraction for the cylindric heat source

describes the energy fraction that will be introduced

through the cylinder the remaining energy will be

introduced via the surface heat source.● The energy fraction of the cylinder is

typically between 0.7 and 0.). The bigger

the cup form of the melt pool the higher is

the energy fraction for the heat source

&energy fraction'cylinder 80.7,.

● The surface depth of the surface heat source defines

the search depth to detect the surface where the

energy should be introduced.

A first pre-check of the heat source can be done inthe three-dimensional model vie.

● The heat source can be visuali9ed by choosing an

appropriate view in the model window and activating

the display of edges and transparency:

● $se only thermal solution; to save time and memory

for the calibration.

1




● 5t is not necessary to simulate the entire weld seam

for the calibration. The simulation can be stopped as

soon as the temperature distribution is inappropriate

or has reached a stationary state.

● The modeled dimensions of the molten 9one can be

visuali9ed by the weld monitor.

The aim of the heat source calibration is to model the

isothermal surface of the real melt pool and the heat

flow through this isothermal surface.

● The weld monitor can display two'dimensional cross

sections with the dimensions of the weld pool along

the whole weld path. The position of the cross

section can be displayed in the three'dimensional

view. $sing a scroll bar the user can check all cross

sections along the weld path.

● /dditionally a user can compare the dimensions of

the heat affected 9one with the dimensions of the

isothermal lines of the transformation temperatures /( and /3.

heatsourcegeometry en

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