I have created a model:

from odoo import models, fields, api

class ArticleNumber(models.Model):
    _name = "article.number"
    _description = "Article Number"

    name = fields.Char('Name', index=True, required=True, translate=True)
    article_number = fields.Char()
    product_id = fields.Many2one('product.product', string="Product")
    date = fields.Date()

Now when I load that in, inside the sale.order.line with this:

from odoo import models, fields, api


class SaleOrder(models.Model):
    _inherit = "sale.order"


class SaleOrderLine(models.Model):
    _inherit = "sale.order.line"

    article_id = fields.Many2one('article.number', 'Article Number', change_default=True, ondelete='restrict')

and here in the view:

<?xml version="1.0" encoding="utf-8"?>
<odoo>
  <data>

    <record id="sale_order_form" model="ir.ui.view">
        <field name="name">sale.order.form</field>
        <field name="model">sale.order</field>
        <field name="inherit_id" ref="sale.view_order_form"/>
        <field name="arch" type="xml">
            <xpath expr="/form/sheet/notebook/page/field[@name='order_line']/tree/field[@name='name']" position="after">
                <field name="article_id"/>
            </xpath>
        </field>
    </record>

  </data>
</odoo>

I get this back: 

I only want the Name there, not the object,id 

What is wrong here?