SetDefaultChart Method
Specifies the name of the chart template that Microsoft Excel will use when creating new charts.
expression.SetDefaultChart(FormatName)
expression Required. An expression that returns an Application object.
FormatName Optional Variant. Specifies the name of a custom autoformat. This name can be a string naming a custom autoformat, or it can be the special constant xlBuiltIn to specify the built-in chart template.
Example
This example sets the default chart template to the custom autoformat named "Monthly Sales."
Application.SetDefaultChart FormatName:="Monthly Sales"