AspNetCore.Docs/aspnet/whitepapers/aspnet4/overview/samples/sample60.aspx

<asp:ChartArea Name="ChartArea1">

  <axisy>

    <ScaleBreakStyle 
        BreakLineStyle="Wave" 
        CollapsibleSpaceThreshold="40" 
        Enabled="True" />
  </axisy>

<%-- Additional markup here --%>
</asp:ChartArea>